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Under natural short days (SDs), low-intensity lighting during the middle of a night (night interruption, NI) can control flowering of daylength-sensitive ornamentals. Red (R, 600-700 nm) and far-red (FR, 700-800 nm) radiation is primarily absorbed by phytochromes that mediate flowering, whereas blue (B, 400-500 nm) radiation typically has less photoperiodic relevance, at least at a low intensity. White (W) light-emitting diodes (LEDs) emit photons over a broad spectrum; however to our knowledge, their efficacy at regulating flowering has not been published. We investigated whether white LEDs controlled flowering of five long-day plants [calibrachoa (Calibrachoa × hybrida), coreopsis (Coreopsis grandiflora), petunia (Petunia × hybrida), rudbeckia (Rudbeckia hirta), and snapdragon (Antirrhinum majus)] and two SD plants [chrysanthemum (Chrysanthemum × morifolium) and marigold (Tagetes erecta)]. Plants were grown in a greenhouse at 20°C under 9-h SDs with or without 4-h NIs from R, B+R, cool-W, warm-W, or R+W+FR LEDs. Irradiance at plant canopy was adjusted to approximately 2 µmol m-2 s-1 between 400 and 800 nm. Compared with SD, all NIs similarly promoted flowering of calibrachoa and rudbeckia; however, only R+W+FR promoted flowering of snapdragon. NIs without FR radiation (i.e., R, B+R, cool-W, and warm-W) accelerated flowering of coreopsis and petunia, but flowering under R+W+FR was 11-16% earlier than under the other NIs. R+W+FR was less effective than the other NIs at inhibiting flowering of chrysanthemum and marigold. Cool-W and warm-W had similar effects on flowering and development of all crops. Plant height of calibrachoa, coreopsis, and marigold at flowering was greatest under R+W+FR; however, stem length of the other crops was similar under all NIs. We conclude that W LEDs inhibited flowering of SD plants and were as effective as R or R+W+FR radiation at promoting flowering of some, but not all, long-day plants.

When the natural photoperiod is short, electric lighting can be used to promote flowering of a wide range of ornamental long-day plants (LDP) grown inside greenhouses. A combination of red (R; 600–700 nm) and far-red (FR; 700–800 nm) radiation is effective when delivered at a low intensity (1–2 μmol m−2 s−1), but recent research shows blue (B; 400–500 nm) radiation can also be effective. We performed an experiment, replicated in time, that identified the B photon flux density that controlled flowering of four LDPs when delivered as a 4-h night interruption (NI) or 7-hour day extension (DE) during an otherwise 15-h night. Seedlings of four annual bedding plants were initially grown under a 9-h day, and then were transferred to one of seven lighting treatments, where subscripts indicate their photon flux densities: R+FR2–3 NI; B5, B15, or B30 NI; and B5, B15, or B30 DE. At a sufficiently high photon flux density, B radiation delivered as a 4-h NI or 7-h DE promoted flowering of all four LDPs. All species exhibited a dose-response relationship between B photon flux density and flowering time. The threshold B photon flux density above which flowering was promoted varied among the four LDPs, and was 5 μmol m−2 s−1 for coreopsis (Coreopsis grandiflora) and snapdragon (Antirrhinum majus) and 15 μmol m−2 s−1 for petunia (Petunia × hybrida) and rudbeckia (Rudbeckia hirta). A B photon flux density of 15 or 30 μmol m−2 s−1 delivered as an NI or DE was usually as effective as 2–3 μmol m−2 s−1 of R + FR radiation for all LDPs tested. We conclude that while flowering of LDPs is more sensitive to R + FR than B radiation, relatively low B photon flux densities are perceived as a long day when delivered as a DE or NI.

Scheduled production of ornamentals has facilitated the development of novel crop lines that can be sold in flower over an extended period, thereby maximising sales potential. Research activities have aided the development of protocols for these ‘forced’ crops, but little attention has been given to knowledge of how such protocols affect subsequent garden performance. The aim of this study therefore, was to investigate the influence of different production factors (cutting size, temperature, photoperiod and time of propagation) on flower induction both with respect to the main marketing stage, but also in terms of ‘after-sales’ performance. The short-lived herbaceous perennial Coreopsis grandiflora cv. Flying Saucers was used as a model subject. When exposed to five diurnal temperatures (14, 20, 24, 27 and 31 °C) and grown at four photoperiods (8, 11, 14 and 17 h), time to first open flower was optimal at 27 °C (42 days). Speed of flowering was aided by longer photoperiod (approximately 5 days earlier at 17 h than at 14 h). Greatest numbers of flowers produced overall though was associated with the 14 °C/14 h regime. Comparisons based on original cutting size demonstrated that large cuttings, rooted under long-day photoperiods produced plants with greater flower numbers than other cutting treatments. Once planted out, however, plants from all treatment combinations had similar floral performance (mean of 160 flowers per plant). Time of propagation/planting-out also had no overall effect on the numbers of flowers produced within the lifespan of the plant. It was concluded that conditions during production and planting time did not influence garden performance over the longer term.

Effective population size for conservation of cultivated plants was studied in Coreopsis grandiflora on populations in variants of 1, 5, 10, 30, 50 and 100 individuals. In five consecutive years these traits were studied on seeds originating from parental populations: seed number and weight per infructescence, thousand seed weight and germination. Plant height and flower size were investigated in a field trial. The influence of population size was expressed mainly in traits of early life-history stages. Inbreeding depression influenced germination already in the first year and was similar for the five years while seed weight was influenced from the second year. In the fifth year there were significant differences among variants of 30 individuals and less and variant of 50 individuals in all evaluated traits. The results document that mostly cross-pollinated cultivars of a population smaller than 50 individuals are exposed to impairment. The population of 10 individuals and less is at risk of extinction. This result will be influenced by the level of cross-pollination and degree of selection.

A study was conducted in 2004 and 2005 to determine how ‘Early Sunrise’ coreopsis (Coreopsis grandiflora Hogg ex Sweet. ‘Early Sunrise’), ‘Moonbeam’ coreopsis (Coreopsis verticillata L. ‘Moonbeam’) and ‘Goldsturm’ rudbeckia (Rudbeckia fulgida Aiton ‘Goldsturm’) responded to two plant growth retardants applied at three stages of plant development (SOD) when plants were exposed to night-interrupted lighting (NIL) while grown outdoors under nursery conditions in the southern United States. With few exceptions, height of all species was suppressed by 2 weeks after first treatment (WAT) compared to NIL only, regardless of whether 5000 ppm B-Nine or 20 ppm Sumagic was applied at the beginning of a period of rapid shoot elongation (SOD 2) or 2 weeks prior to (SOD 1) or following this stage (SOD 3), and continued throughout the plants’ vegetative phase, although the level of suppression varied with SOD and PGR. Applying either PGR at SOD 2, when rapid shoot elongation first began, was most effective in suppressing vegetative height of ‘Early Sunrise’ coreopsis and ‘Goldsturm’ rudbeckia, whereas vegetative height suppression of ‘Moonbeam’ coreopsis was not affected by SOD when Sumagic was applied, but suppression was greatest when B-Nine was applied at SOD 1, two weeks before rapid shoot elongation began. ‘Early Sunrise’ coreopsis and ‘Goldsturm’ rudbeckia were shortest at first flower when PGRs were applied at SOD 2 and SOD 3, respectively, but plant height of ‘Moonbeam’ coreopsis at first flower was not affected by SOD. Where differences in height suppression occurred at first flower, B-Nine was more effective than Sumagic. Plant SOD when PGRs were applied had no effect on flowering or plant quality of ‘Moonbeam’ coreopsis and minimal effect on ‘Early Sunrise’ coreopsis or ‘Goldsturm’ rudbeckia.

A study was conducted in 2004 to determine if end-of-day lighting (EOD) alone or in combination with night-interrupted lighting (NIL) could be used to suppress stem elongation of ‘Goldsturm’ coneflower (Rudbeckia fulgida Aiton ‘Goldsturm’), ‘Moonbeam’ coreopsis (Coreopsis verticillata L. ‘Moonbeam’) and ‘Early Sunrise’ coreopsis (Coreopsis grandiflora Hogg ex Sweet. ‘Early Sunrise’) when grown outdoors under nursery conditions in the southern U.S. without negating the benefits of earlier flowering from NIL. End-of-day lighting, NIL, and the combination of the two treatments accelerated time to flowering of all three cultivars compared to that of plants under a natural photoperiod (NP); however, rudbeckia flowered quicker when exposed to NIL or NIL + EOD than when grown under EOD only. Height of rudbeckia grown under EOD or NIL was greater than that of plants grown under NP, whereas ‘Moonbeam’ coreopsis exposed to EOD, NIL or EOD + NIL were similar in height and taller than plants grown under NP. Height of ‘Early Sunrise’ coreopsis was minimally affected by treatments, except that plants under EOD were shorter than those under EOD + NIL. Growth index, flower number, shoot length and quality rating were similar in almost all cases for plants of the three cultivars when grown under EOD lighting, NIL, or EOD + NIL. These results indicate EOD was ineffective in suppressing height growth and provided no benefit, either alone or in combination with NIL, over NIL alone in the accelerated production of these cultivars outdoors under nursery conditions.

During our experiment the effect of chlorocholine chloride, Caramba, Cultar, Regalis and Toprex bioregulators were examined on some annual ornamental species. The species used for the experiment were Coreopsis grandiflora, Godetia grandifolra , Scabiosa atropurpurea and Matthiola incana. The aim of this work was to produce marketable, bushy habitat annual plants as flowering pot plants with the use of retardants. The experiment was carried out from April to September 2013, plants were treated beweekly. Â It was found that all the treatments had effect on the plants but the result depended on the species. In the case of Coreopsis grandiflora the best dwarfing effect was obtained with Regalis 0,25% and Caramba at 0,05% concentration, the maximum shorten rate was 50%. In the case of the other examined species intensive retardant effect was observed with the spray of Cultar, Toprex or Caramba. Best results were obtained by the treatment of Matthiola incana , all the chemicals resulted compact, bushy, decorative plant habitat, Regalis WG had the best results among the bioregulators. The chlorophyll content of two plant species was measured: Scabiosa atropurpurea and Matthiola incana . The chlorophyll content of the leaves was reduced by using growth retardants. The rate of decrease depended on the regulator type and the plant species. By cultivation for market is mandatory to do trial management before use. Â Â

A greenhouse experiment was carried out to study the effects of the sterilization of the soil on the invasive weed Coreopsis grandiflora Hogg. at two irradiance levels. The sterilization was done by benomyl which is a fungicide used worldwide to sterilize the fungal pathogens. The study found that the effects of the sterilization on C. grandiflora varied with the light intensity in terms of the leaf biomass, total biomass and the root-shoot ratio. At high irradiance (60%) the sterilization significantly increased the leaf biomass, total biomass and the ability of photosynthesis of C. grandiflora, suggesting there are soil pathogenic fungi which contribute to biotic resistance against the invasive plants. In contrast, at low irradiance, the sterilization did not have significant effects on the biomass of the plant although the Fv/Fm was significantly increased, suggesting that the light was the key factor and the biotic resistance of soil biota have some minor effects on the plant invasion of C. grandiflora in low light habitat such as forest canopy. The biotic resistance of soil biota on C. grandiflora varies with irradiance levels, suggesting the limiting factors of invasive plants are complex and vary with microhabitats.

The natural photoperiod is often modified in the commercial production of floriculture crops to promote or inhibit flowering. In addition, low-intensity lighting is sometimes provided in growth chambers to influence flowering of photoperiodic plants. Incandescent (INC) lamps have been commonly used to provide photoperiodic lighting, but they are being phased out of production because of their energy inefficiency. Here, we compared flowering and morphological responses of two short-day chrysanthemum ( Chrysanthemum × grandiflorum ) potted varieties and four long-day (LD) plants grown in a controlled environment greenhouse at 20 °C with a truncated 9-h day and a 2- or 4-h night interruption (NI) or 6-h day extension (DE) lighting with INC lamps, compact fluorescent lamps (CFLs), or a combination of the two (INC + CFLs). Bulb type had no effect on flowering percentage of campanula ( Campanula carpatica ‘Pearl Deep Blue’), coreopsis ( Coreopsis grandiflora ‘Early Sunrise’), petunia ( Petunia × hybrida ‘Wave Purple Classic’), and rudbeckia ( Rudbeckia hirta ‘Becky Cinnamon Bicolor’). Within bulb type, the LD lighting regimen had no effect on flowering percentage, with the exception of chrysanthemum ‘Bianca’, in which the 4-h NI inhibited flowering more than the 2-h NI or 6-h DE treatments. However, petunia that received a 4-h NI or 6-h DE from CFLs flowered 2–3 weeks later than when the lighting treatments were provided by INC lamps. Therefore, complete replacement of INCs with CFLs can delay flowering in some crops such as petunia, whereas a hybrid approach (INC + CFL) or use of lamps that emit far-red light can alleviate this potential problem.

In September 2018 symptoms of little leaf were observed in Coreopsis grandiflora located in flower nurseries at IARI campus, New Delhi. Little leaf and phyllody symptoms were also observed on nearby growing ornamental hedge plants belonging to Duranta genus and in a weed (Parthenium hysterophorus). Amplicons of ∼1.25 kb were consistently amplified with nested PCR assays using DNA extracted from the symptomatic Coreopsis, Duranta and Parthenimum samples, while no amplification was observed with any of the asymptomatic samples of the same species. Leafhoppers (Empoasca sp.) collected from the nurseries of Coreopsis were also found phytoplasma positive using the same nested PCR protocol. BLAST and pair wise sequence comparison of the R16F2n/R2 region of 16S rRNA gene of C. grandiflora little leaf (CGLL), Duranta sp. little leaf (DLL), P. hysterophorus phyllody (PHP) and Empoasca sp (Em) revealed 99.8% sequence identity with the ‘Candidatus Phytoplasma australasia’ sequence. Phylogeny and virtual RFLP analysis with iPhyclassifier confirmed the affiliation to ‘Ca. P. australasia’, subgroup 16SrII-D of all these phytoplasma strains. Amplicons of the expected size were also consistently amplified from these strains with primers specific to 16SrII group of SAP11, imp and tuf genes. All the amplified products were sequenced and confirmed the phytoplasma affiliation to 16SrII-D subgroup. This is the first report of 16SrII-D group phytoplasma presence in C. grandiflora showing little leaf disease.

Pine bark (PB) for horticultural uses is becoming less available and as a result, there is a need to develop alternative substrates for continued profitability of the nursery industry. This study, conducted at Poplarville, MS, and Auburn, AL, evaluated the growth of nine perennial species in a substrate composed of a pulpwood harvesting by-product called clean chip residual (CCR) which contains approximately 50% wood fiber. Two CCR particle sizes were used alone or amended with peat moss (PM) (4:1 by vol) and compared with control treatments PB and PB:PM. Substrates composed of 100% PB or 100% CCR had high air space (AS) and low water holding capacity (WHC) which resulted in less available water to plants. Addition of PM lowered AS and increased WHC. There were no significant differences among growth indices at Poplarville for 6 of 8 species and for 3 of 7 species at Auburn, though the remaining 4 species were only slightly smaller when grown in 100% CCR. Shoot dry weight was greatest in substrates amended with PM. Results of this study indicate that acceptable growth of perennial plants can be obtained in substrates composed of CCR when compared to PB and PB amended with PM. Index words: media, forest residuals, pine, Loblolly, peat moss, pine bark, sustainable. Species used in this study: loblolly (Pinus taeda L.); butterfly bush (Buddleia davidii ‘Pink Delight’ Franch.); gaura (Gaura lindheimeri ‘Siskiyou Pink’ Engelm. & A. Gray); coreopsis (Coreopsis grandiflora ‘Early Sunrise’ Hogg ex Sweet); coreopsis (Coreopsis rosea ‘Sweet Dreams’ Nutt.); verbena (Verbena canadensis ‘Homestead Purple’ (L.) Britt.); scabiosa (Scabiosa columbaria ‘Butterfl y Blue’ L.); dianthus (Dianthus gratianopolitanus ‘Firewitch’ Vill.); rosemary (Rosemarinus offi cinalis ‘Irene’ L.); salvia (Salvia guaranitica ‘Black and Blue’ St.-Hil. ex Benth.).

In order to understand the relationship between genetic diversity and the invasiveness of exotic plants, genetic diversity was studied in the invasive plant Coreopsis grandiflora Hogg. at different altitudes in Laoshan Mountain, Northern China. Coreopsis grandiflora has produced a great deal of damage in Laoshan Mountain. Its genetic diversity was examined using 16 random amplified polymorphic DNA (RAPD) primers, and 125 bands were collected from all individuals. The mean percentage of polymorphic loci (P%) was 39.54%, and the total percentage of polymorphic loci (P%) was 86.40%. The mean Shannon's Information index (H0) was 0.2326 and the mean Nei's genetic diversity (H) was 0.1596. These results indicated a comparatively high genetic diversity in C. grandiflora in Laoshan Mountain. The genetic differentiation among populations (GST) was 0.3948, indicating that most genetic diversity occurs within populations. On the whole, the abundance and the genetic diversity of C. grandiflora decreased with increasing altitude. The high genetic diversity may be related to the invasion of C. grandiflora in Laoshan Mountain. Key words: Biological invasions, Coreopsis grandiflora Hogg., genetic distance, genetic diversity, random amplified polymorphic DNA (RAPD), sexual reproduction, Shannon’s information index

Night-interrupted lighting (NIL) outdoors in a southern nursery setting was evaluated as a system for accelerated production of herbaceous perennials requiring long days to flower. Treatments were NIL beginning February 1, February 15, March 1, or March 15, and a natural photoperiod control. Compared to plants under the natural photoperiod and depending upon initiation of NIL treatment and year, NIL accelerated and increased flowering of ‘Moonbeam’ coreopsis (Coreopsis verticillata L. ‘Moonbeam’) 7 to 36 days and 20 to 244%, ‘Early Sunrise’ coreopsis (Coreopsis grandiflora Hogg ex Sweet. ‘Early Sunrise’) 3 to 20 days and 26 to 64%, ‘Sunray’ coreopsis (Coreopsis grandiflora Hogg ex Sweet. ‘Sunray’) 6 to 13 days and 21 to 44%, ‘Autumn Joy’ stonecrop (Sedum x ‘Autumn Joy’) 26 to 57 days and 200 to 300%, and ‘Blue Queen’ salvia (Salvia x superba Stapf ‘Blue Queen’) 7 to 12 days and 56 to 83%. Flowering of ‘Red Beauty’ obedient plant (Physostegia virginiana (L.) Benth. ‘Red Beauty) was accelerated 20 to 54 days; however, inflorescence counts decreased 38 to 46% in one year and was not affected by treatments in the second year. Plants of all cultivars, except ‘Autumn Joy’ sedum and ‘Red Beauty’ obedient plant, were taller when exposed to NIL than when grown under the natural photoperiod, however plant quality rating of all cultivars was as high or higher under NIL.

The influence of daily light integral (DLI) before vernalization and vernalization temperature and duration on growth and flower development was determined for seed-propagated perennials Aquilegia ×hybrida Sims `Remembrance', Coreopsis grandiflora Hogg ex Sweet `Sunray', and Lavandula angustifolia Mill. `Hidcote Blue'. Seedlings were grown under two DLIs (4 or 14 mol·m-2·d-l) for 5 weeks before being vernalized at -2.5, 0, 2.5, or 5 °C for 2,4,5, or 8 weeks. `Remembrance' and `Sunray' plants were vernalized in the dark, while `Hidcote Blue' plants were vernalized in light at 5 to 10 μmol·m-2·s-l for 9 hourslday. After vernalization, plants were forced under a 16-h photoperiod in the greenhouse at 20±2 °C. `Remembrance' plants flowered uniformly when vernalized at 0 to 2.5 °C for 2 weeks or longer, and flower number, plant height, time to visible bud or to flower were generally not influenced by vernalization temperature or duration. No `Sunray' plants flowered without vernalization, and only a low percentage flowered with 4-week vernalization. Compared with low DLI, a 14 mol·m-2·d-1 before vernalization delayed flowering by 7 to 20 days in `Remembrance', but there were no substantial differences in flowering characteristics of `Sunray'. `Hidcote Blue' plants were best vernalized in the light at 5 °C for 8 weeks to obtain rapid and uniform flowering and the highest number of inflorescences. Flowering and survival percentages of `Hidcote Blue' were much lower for plants at 14 mol·m-2·d-l DLI compared to 4 mol·m-2·d-1.

Highlights • The first PPO gene (cgAUS1) involved in 4-deoxyaurone formation is identified. • AUS1 is expressed as latent pro-enzyme in E. coli and purified to homogeneity. • Diphenolase activity of AUS1 pro-enzyme is proven using SDS as an activation agent. • Gene expression studies suggest a physiological role for AUS1 in aurone formation., Polyphenol oxidases are involved in aurone biosynthesis but the gene responsible for 4-deoxyaurone formation in Asteraceae was so far unknown. Three novel full-length cDNA sequences were isolated from Coreopsis grandiflora with sizes of 1.80 kb (cgAUS1) and 1.85 kb (cgAUS2a, 2b), encoding for proteins of 68–69 kDa, respectively. cgAUS1 is preferably expressed in young petals indicating a specific role in pigment formation. The 58.9 kDa AUS1 holoproenzyme, was recombinantly expressed in E. coli and purified to homogeneity. The enzyme shows only diphenolase activity, catalyzing the conversion of chalcones to aurones and was characterized by SDS–PAGE and shot-gun type nanoUHPLC–ESI-MS/MS.

For many long-day plants (LDP), adding far red light (FR, 700 to 800 nm) to red light (R, 600 to 700 nm) to extend the day or interrupt the night promotes extension growth and flowering. Blue light (B, 400 to 500 nm) independently inhibits extension growth, but its effect on flowering is not well described. Here, we determined how R-, FR-, or B-deficient (Rd, FRd, or Bd, respectively) photoperiods influenced stem extension and flowering in five LDP species: Campanula carpatica Jacq., Coreopsi ×grandiflora Hogg ex Sweet, Lobelia ×speciosa Sweet, Pisum sativum L., and Viola ×wittrockiana Gams. Plants were exposed to Rd, FRd, Bd, or normal (control) 16-hour photoperiods, each of which had a similar photosynthetic (400 to 700 nm) photon flux. Compared with that of the control, the Rd environment promoted extension growth in C. carpatica (by 65%), C. ×grandiflora (by 26%), P. sativum (by 23%), and V. ×wittrockiana (by 31%). The FRd environment suppressed extension growth in C. ×grandiflora (by 21%), P. sativum (by 17%), and V. ×wittrockiana (by 14%). Independent of the R: FR ratio, the Bd environment promoted stem extension (by 10% to 100%) in all species, but there was little or no effect on flowering percentage and time to flower. Extension growth was generally linearly related to the incident wide band (100 nm) R: FR ratio or estimated phytochrome photoequilibrium except when B light was specifically reduced. A high R: FR ratio (i.e., under the FRd filter) delayed flower initiation (but not development) in C. carpatica and C.×grandiflora and inhibited flower development (but not initiation) in V.×wittrockiana. Therefore, B light and the R: FR ratio independently regulate extension growth by varying magnitudes in LDP, and in some species, an FRd environment can suppress flower initiation or development.

The effectiveness of cool-white fluorescent, high-pressure sodium, incandescent, and metal halide lamps for inducing flowering through daylength extensions in Campanula carpatica Jacq. `Blue Clips', Coreopsis grandiflora Hogg ex Sweet `Early Sunrise', and Coreopsis verticillata L. `Moonbeam' was compared. Lighting was delivered as a 7-hour day extension with photosynthetic photon flux (PPF) ranging from 0.05 to 2.0 μmol·m-2·s-1 following a 9-hour natural daylength. Threshold irradiance values for flowering ranged from -2·s-1, depending on species. Saturation irradiance values for Campanula carpatica `Blue Clips' and C. grandiflora `Early Sunrise' were between 0.2 ± 0.2 and 0.7 ± 0.5 μmol·m-2·s-1, and did not differ between lamps. An irradiance of 1.0 μmol·m-2·s-1 from any lamp was adequate for flowering in Coreopsis verticillata `Moonbeam'. Time to flower at irradiances above the saturation points did not differ significantly between lamp types for all species tested. Campanula carpatica `Blue Clips' and Coreopsis grandiflora `Early Sunrise' plants had significantly longer stems under incandescent lamps than in any other treatment. Coreopsis verticillata `Moonbeam' plants grown under cool-white fluorescent lamps had stems ≈10% longer than those grown under high-pressure sodium or incandescent lamps.

Six long-day species of herbaceous perennials were grown under six night-interruption (NI) photoperiod treatments to determine their relative effectiveness at inducing flowering. Photoperiods were 9-hour natural days with NI provided by incandescent lamps during the middle of the dark period for the following durations: 0.5, 1, 2, or 4 hours; 6 minutes on, 54 minutes off for 4 hours (10% or 6/54 cyclic lighting); or 6 minutes on, 24 minutes off for 4 hours (20% or 6/24 cyclic lighting). For five species, the experiment was repeated with more mature plants; for the sixth, Rudbeckia fulgida Ait. `Goldsturm', following a cold treatment of 8 weeks at 5 °C. The species generally showed a quantitative flowering response to the NI duration until a saturation duration was reached; as the length of the uninterrupted night break increased, flowering percentage, uniformity, and number and plant height increased and time to flower decreased. Minimum saturation durations of NI were 1 hour for Coreopsis grandiflora Hogg ex Sweet `Early Sunrise' and Hibiscus moscheutos L. `Disco Belle Mixed', 2 hours for Campanula carpatica Jacq. `Blue Clips' and Coreopsis verticillata L. `Moonbeam', and 4 hours for unchilled R. fulgida `Goldsturm'. Echinacea purpurea Moench `Bravado' flowered similarly across all lighting treatments. The 6/24 cyclic lighting regimen induced flowering comparable to that under a continual 4-hour NI for four of the six species and the cold-treated R. fulgida `Goldsturm'. Flowering under the 6/54 regimen was generally incomplete, nonuniform, and delayed compared to that under saturation duration treatments. Three of five species flowered earlier when more mature plants were placed under the NI treatments. Cold-treated R. fulgida `Goldsturm' flowered more rapidly than unchilled plants and the saturation duration of NI decreased to 1 hour.

Scheduling crops to flower on specific dates requires a knowledge of the relationship between temperature and time to flower. Our objective was to quantify the effect of temperature on time to flower and plant appearance of four herbaceous perennials. Field-grown, bare-root Coreopsis grandiflora (Hogg ex Sweet.) `Sunray', Gaillardia ×grandiflora (Van Houtte) `Goblin', and Rudbeckia fulgida (Ait.) `Goldsturm', and tissue culture—propagated Leucanthemum ×superbum (Bergman ex J. Ingram) `Snowcap' plants were exposed to 5 °C for 10 weeks and then grown in greenhouse sections set at 15, 18, 21, 24, or 27 °C under 4-hour night-interruption lighting until plants reached anthesis. Days to visible bud (VB), days to anthesis (FLW), and days from VB to FLW decreased as temperature increased. The rate of progress toward FLW increased linearly with temperature, and base temperatures and degree-days of each developmental stage were calculated. For Coreopsis, Leucanthemum, and Rudbeckia, flower size, flower-bud number, and plant height decreased as temperature increased from 15 to 26 °C.

The juvenile phase of Coreopsis grandiflora `Sunray', Gaillardia×grandiflora `Goblin', Heuchera sanguinea `Bressingham', and Rudbeckia fulgida `Goldsturm' was characterized by exposing plants with 0 to 20 nodes to cold treatments at 5°C. After 0, 10, or 15 weeks cold treatment, plants were grown at constant 20° C under a 9 h photoperiod with 4 h night-interruption lighting (22:00 to 02:00 h; long days) or under a 9 h photoperiod (short days). Based on flowering percentage and time to flower, we concluded that the juvenile phase of Coreopsis, Gaillardia, Heuchera, and Rudbeckia ended when they had approximately 8, 16, 19, and 10 nodes, respectively. Coreopsis required cold treatments to flower. A cold treatment was not required for flowering of Gaillardia and Rudbeckia; however, such treatment improved their flowering percentage and greatly accelerated flowering. Increasing cold duration from 10 to 15 weeks did not influence time to flower of Coreopsis, Gaillardia, and Rudbeckia; however, the increase enhanced flowering percentage of Coreopsis and Gaillardia and hastened flowering of Heuchera. Heuchera was a day-neutral plant after ten weeks cold treatment, Rudbeckia was an obligate long-day plant, and Gaillardia and Coreopsis were quantitative long-day plants.

The orange-yellow colouration of Coreopsis grandiflora is mainly provided by the 6′-deoxychalcone butein and its 4′-glucoside respectively, as well as the corresponding 4-deoxyaurones sulfuretin and leptosidin (7-methoxysulfuretin) and their 6-glucosides. Incubation of butein or sulfuretin with enzyme preparations from petals of Coreopsis grandiflora in the presence of uridine 5′-diphosphoglucose led in each case to the formation of one single product, which was identified as butein 4′-glucoside and sulfuretin 6-glucoside, respectively. The 6′-deoxychalcone isoliquiritigenin was a poor substrate. Glucosylation of hydroxyl groups in other positions was not observed. Naringenin chalcone and eriodictyol chalcone were not accepted as substrates. The glucosylation reaction of butein and sulfuretin exhibited an optimum at pH 8.0 and 7.0, respectively. Bivalent ions like Mg2+ and Ca2+ stimulated only slightly, whereas the addition of Cu2+, Zn2+, N-ethylmaleimide and p- hydroxymercuribenzoate led to a total loss of enzyme activity. The apparent Km values for butein and sulfuretin were 146 and 44 μM, respectively. The specific enzyme activity increased slowly during bud and flower development and declined in the later stages. The highest specific activity was observed in open flowers with 30 mm diameter. The rates of the glucosylation reaction with butein and sulfuretin had similar patterns.

The leaching of arsenic (As) from plant growth medium, admixed with different proportions of composted biosolids in field containers, was determined over a four-month period. Eight-week-old perennial flowers, Coreopsis grandiflora L, were transplanted in the field in 2-L containers filled with plant growth media. The treatments were replicated three times and rainfall was supplemented to supply 2 cm of water per day. Water percolating through potted plant containers was collected biweekly and analyzed for As using graphite furnace atomic spectrometry. The concentrations of As in the leachates increased with increasing proportions of compost in the medium and decreased with time of leaching, generally remaining below the drinking water standard of 50 μg/L after two months. Leaching of As occurred at a rapid rate initially but then continued at a slow rate. Compared to other metals of concern, as Cd, Cr, Ni and Pb, As in the compost appeared more mobile.

To examine the effects of chilling and a limited inductive photoperiod (LIP) on flowering of Chrysanthemum superbum Bergmans ex J. Ingram `G. Marconi' and `Snow Lady', Coreopsis grandiflora Hogg `Sunray', and Coreopsis lanceolata L. `Early Sunrise', seeds were sown and plants were maintained in the greenhouse in short days (SDs) for 7 weeks, followed by 4 months of natural outdoor chilling for all plants except 10 of each cultivar, which remained in the greenhouse under SDs for the duration of the experiment. Upon return to greenhouse conditions, 10 plants of each cultivar were placed in SDs, all other chilled plants were placed in long-days (LDs) and subsequently transferred to SDs after receiving 6, 8, 10, 12, 14, 16, 18, 20, or 22 LD cycles. Ten chilled plants of each cultivar remained in LDs for the duration of the experiment. Continuous SDs without chilling resulted in 70%, 40%, 20%, and 10% flowering in `Snow Lady', `Early Sunrise', `Sunray,' and `G. Marconi', respectively. Chilling, followed by a return to continuous SDs, improved flowering in all cultivars compared to SDs without chilling. The number of LD cycles required for 100% flowering varied with cultivar. Ninety percent of the chilled `Early Sunrise' plants flowered with no LD cycles, and 100% flowering was produced by as few as six LD cycles. In `Snow Lady', 100% flowering occurred in chilled plants with no LD cycles and those receiving at least 10 LD cycles. With only six or eight LD cycles, 90% and 80% of these plants, respectively, still flowered. The percentage of `G. Marconi' and `Sunray' plants flowering ranged from 40% to 100% in the chilled treatments, with a general trend for more flowering with an increase in the number of LD inductive cycles. Continuous LDs following chilling resulted in as high or higher percent flowering than any other treatments (100% for `G. Marconi' and 90% for `Sunray'). The effects of LIP were evident in both Coreopsis cultivars but in neither Chrysanthemum superbum cultivar. There was a linear relationship between the number of LDs received and stem length at first flower in `Sunray' and `Early Sunrise'. In both cultivars, a reduction in stem elongation of about 10 cm occurred when plants received only 6 LDs compared to 22 LDs. The number of days from the start of LDs to first flower increased linearly as the number of LD cycles before the transfer back to SDs increased.

Existing methods for analyzing nucleotide diversity require investigators to identify relevant hierarchical levels before beginning the analysis. We describe a method that partitions diversity into hierarchical components while allowing any structure present in the data to emerge naturally. We present an unbiased version of Nei's nucleotide diversity statistics and show that our modification has the same properties as Wright's F ST. We compare its statistical properties with several other F ST estimators, and we describe how to use these statistics to produce a rooted tree of relationships among the sampled populations in which the mean time to coalescence of haplotypes drawn from populations belonging to the same node is smaller than the mean time to coalescence of haplotypes drawn from populations belonging to different nodes. We illustrate the method by applying it to data from a recent survey of restriction site variation in the chloroplast genome of Coreopsis grandiflora.

The effect of harvest dates between September and December on regrowth after storage of field-grown Coreopsis grandiflora Hogg × Sweet `Sunburst' and `Sunray', Geum quellyon Sweet `Mrs. Bradshaw', Gypsophila paniculata L. `Snowflake', Iberis sempervirens L. `Snowflake', and Dicentra spectabilis (L.) Lem. crowns was determined. After 0 to 7 months of storage at 0C, stored crowns were repotted and grown in a greenhouse. Plants from later harvests were of higher quality than those from earlier harvests, showing higher rates of survival after longer storage periods, less mold development in storage, and stronger regrowth after storage. Late field harvest is recommended for optimum storage quality.

According to the distribution of Coreopsis grandiflora Hogg., samples were collected from two natural invasion sites; Jufeng and Beijiushui and cultivated site to research AM fungal arbuscule structure of C. grandiflora Hogg., colonization status in different sample plotsand altitudes, and the correlation between colonization status and soil factors in the rhizosphere of C. grandiflora. The result showed that C. grandiflora could form heavyParis-type arbuscule structure, Beijiushui mycorrhizal colonization percentage and numbers of entry points was highest and significant differences with Jufeng and campus.C. grandiflora Hogg. mycorrhizal colonization percentage was on the rise with rising altitudes. In addition to altitudes, soil factors as well as to influence AM fungal colonizationstatus, there were very positive correlation (r=0.792) and positive correlation (r=0.725) between mycorrhizal colonization percentage and the content of organic carbon, availablepotassium in soil, respectively; there were very positive correlation (r=0.854) and very negative correlation (r=-0.966) between numbers of vesicles P-type arbuscule) and the content of available potassium, pH in soil; there were negative correlation (r=-0.782) between numbers of entry points and the content of available phosphorus. High infection rate and the formation of typical arbuscular form of C. grandiflora Hogg. at Laoshan should have an important role on the process from the invasion to becoming constructive species. Key words: Coreopsis grandiflora, Arbuscular mycorrhiza fungi (AM fungi), mycorhizae structure, soil factors.

Juvenility and flowering requirements of Coreopsis grandiflora Hogg ex Sweet. `Sunray' and C. lanceolata L. `Early Sunrise' were examined by growing plants under short days (SD) and transferring them to long days (LD) upon reaching the designated true leaf stages. Neither cultivar flowered in continuous SD, and `Sunray' remained vegetative in LD. However, LD induced flowering in `Early Sunrise' plants in each leaf count treatment and the loss of juvenility was gradual, with most rapid flowering occurring when plants were transferred to LD at the 16 leaf stage. The limited inductive photoperiod (LIP) inhibited stem elongation of `Early Sunrise' plants in all LD treatments and selectively inhibited axillary flower bud development compared to plants grown in continuous LD. LIP did not affect scape length at first flower even though plant height was significantly diminished if given relatively few LD before transfer to SD. Height reduction was attributed to LIP inhibition of stem elongation with no significant loss of axillary flower bud potential.

The chemical composition of essential oils isolated by hydrodistillation of leaves of Coreopsis barteri Oliv. & Hiern and Coreopsis grandiflora Hogg ex Sweet were analysed by capillary GC and GC-MS. Limonene (55.4%) and α-phellandrene (12.9%) were found to be the major constituents of C. barteri oil whereas germacrene-D (42.1%) and myrcene (11.7%) predominate in the volatile extract of C. grandiflora ; besides these two terpene hydrocarbons, the latter oil contains minor but significant amounts of two rather unusual compounds : 1-phenyl-1,3,5-heptatriyne (5.2%) and precocene I (0.9%)

Field-grown plants of Alcea rosea (L.) Cav. (hollyhock), Asparagus officinalis L., Coreopsis grandiflora Hogg ex Sweet `Sunray', Dicentra spectabilis (L.) Lem. (bleeding heart), Gaillardia ×grandiflora Van Houtte `Baby Cole', Lupinus polyphyllus Lindl. `Russell Hybrids', and Phlox subulata L. `Emerald Pink' harvested as bare-root crowns in late fall were packaged in polyethylene-lined crates and stored for 6 months. There were no significant differences in the regrowth performance of any of the perennials following storage at 0 or -2C. The amount of surface covered by fungal hyphae (surface mold) increased more than 2-fold between 4 and 6 months of storage at 0 or -2C on all species. Dicentra spectabilis and Alcea rosea were most susceptible to mold growth during storage. Alcea rosea and Coreopsis grandiflora stored poorly at all storage temperatures. In a second experiment, the regrowth performance of Artemisia schmidtiana Maxim `Silver Mound', Asclepias tuberosa L., Aster novae-angliae L., Centranthus ruber (L.) DC., Chrysanthemum superbum Bergmans ex. J. Ingram, Dicentra eximia (Ker-Gawl.) Torr., Dicentra spectabilis, Geum quellon Sweet `Mrs. Bradshaw', Hosta `Honeybells', and Lupinus polyphyllus was tested following 6 months of storage at temperatures between -10 and +5C. Regrowth performance was generally similar at -2, 0, and 5C for most species. The results indicated, however, that Centranthus ruber and Chrysanthemum ×superbum should not be stored at temperatures of -2C or below. Sufficient etiolated growth developed for most species when stored at 2C or above to cause problems during shipping, handling, and potting. In general, mold growth on crowns during storage did not reduce regrowth performance of the species tested.

Coreopsis and Gaillardia were exposed to supra-optimal temperatures of 35 °C for a 6-week period beginning at flower initiation. Photosynthesis measurements were recorded at 1100 hr, 1300 hr, and 1500 hr for 3 days each week and carbohydrate partitioning was determined once per week. Results indicate that the time of day the measurements were taken made little difference on rate of photosynthesis and that there was a similar trend in photosynthetic rate over the 6-week period. Photosynthesis decreased as the plants began to flower and then increased until the onset of flower senescence. The patterns of carbohydrate partitioning were similar to those observed for photosynthesis. The plants grown at supra-optimal and optimal conditions had a similar trend and rate of photosynthesis throughout the 6-week period. Plant growth and total carbohydrates significantly decreased as the duration of high temperature increased for both species, however Gaillardia was more heat tolerant than Coreopsis.

Coreopsis grandiflora `Sunray' has been reported to flower under long days (LD) following vernalization or short days (SD). The objectives of this study were to characterize the effective duration of vernalization and SD and to determine if photoperiod during vernalization influences flowering. Vegetative cuttings taken from stockplants developed from one seedling were rooted for 2 weeks and grown for 5 weeks. Plants were provided with a 9-hour photoperiod for 2, 4, 6, or 8 weeks or were vernalized at 5 °C under a 16-hour photoperiod for 2, 4, 6 or 8 weeks or under a 9-hour photoperiod for 2 or 8 weeks. Following treatments, plants were grown in a greenhouse at 20 °C under a 16-hour photoperiod. Control plants were grown under constant 9- or 16-hour photoperiod. Leaf development, days to first visible bud (DVB), days to first open flower (DFLW), and height and total number of flower buds at FLW were recorded. No plants flowered under continuous SD. Under continuous LD, two plants flowered on axillary shoots but only after 95 days. All vernalized and SD-treated plants flowered on both terminal and axillary shoots. Photoperiod during vernalization did not affect subsequent flowering. DFLW decreased from 56 to 42 and from 50 to 42 after 2 to 8 weeks of vernalization and SD treatments, respectively. Following 2, 4, 6, and 8 weeks of vernalization, plants had 116, 116, 132, and 204 flower buds, respectively. Plant height at FLW of all SD-treated and vernalized plants was similar. Thus, 2 weeks of 9-hour SD or vernalization at 5 °C followed by LD was sufficient for flowering of our clone of C.`Sunray', although longer durations hastened flowering and increased flower bud number.

Coreopsis grandiflora (tickseed) regenerates readily from leaf segments allowing the possibility to exploit somaclonal variation as a means to develop novel phenotypes. We used true leaves from in vitro seedlings of Coreopsis grandiflora `Domino' grown on MS basal medium as explants in a series of experiments to evaluate the effect of media, leaf explant orientation, and genotype on shoot regeneration. Genotype accounted for most of the variation with two particular seedlings regenerating freely and eight others generally recalcitrant. From these two seedlings, designated E2 and H2, shoots were regenerated and acclimated to the greenhouse over a period of weeks. Once the plants had established (≈6 weeks after acclimatization) they were vernalized by moving them to a lighted bench (12-h photoperiod) in a walk-in cooler at 4 °C .On transfer back into the greenhouse, the plants flowered within a few weeks; 15 of 175 somaclones were selected based on distinct differences in flower orientation and appearance. The selected somaclones were propagated by division and transplanted to the field in May 2002 in a randomized complete-block design with three-plant plots and three replications, to determine if the novel characteristics persisted through an additional propagation cycle. In the field, plant height, leaf dimension, flowering, and flower dimensions were scored in June-July 2003. Significant differences were found between somaclones and the original E2 and H2 similarly propagated seedlings for desirable (more petals per flower, greater flowering, shorter plants), undesirable (less flowering, smaller flowers), and neutral (narrower leaves, taller plants) traits.

Scheduling crops to flower for specific dates requires a knowledge of the relationship between temperature and time to flower. Our objective was to determine the relationship between temperature and time to flower of four herbaceous perennials. Field-grown, bare-root Coreopsis grandiflora `Sunray', Gaillardia grandiflora `Goblin', Rudbeckia fulgida `Goldsturm', and tissue culture-propagated Chrysanthemum superbum `Snow Cap' were exposed to 5C for 10 weeks. They were grown at 15, 18, 21, 24 or 27C under 4-h night interruption lighting. Time to visible bud (VB) and first flower (FLW) were recorded. Days to VB, days to FLW, and days from VB to FLW decreased as temperature increased. Time to flower at 15C was 70, 64, 96, and 54 days and 24, 39, 48, and 36 days at 27C for Coreopsis, Gaillardia, Rudbeckia, and Chrysanthemum, respectively. The 27C temperature apparently caused devernalization on Coreopsis because only 40% of the plants flowered. The effects of temperature on flower size, flower bud number, and plant height also are presented.

Most plants have a postgermination juvenile phase in which flower induction will not occur. Some species require a cold period for flower induction and will not respond to the cold treatments during the juvenile phase. We determined juvenile phases of Coreopsis grandiflora `Sunray', Gaillardia grandiflora `Goblin', Heuchera sanguinea `Bressingham', and Rudbeckia fulgida `Goldsturm'. Plants were exposed to 5C for 0, 10, or 15 weeks when Coreopsis had 0, 2, 4, 6, 8, or 10 leaves (>1 cm); Gallardia, 4, 8, 12, or 16 leaves; Heuchera, 8, 12, 16, or 20 leaves; Rudbeckia, 5, 10, 15, or 20 leaves. Plants were grown under a 4-h night interruption lighting (LD) or under a 9-h photoperiod (SD) after cold treatments. Based on time to flower and final leaf count, the juvenility of Coreopsis, Gaillardia, Heuchera, and Rudbeckia ended when they had about 6, 10, 12, and 15 leaves, respectively. Cold treatments were necessary for flower induction of Coreopsis and Heuchera and they increased the flowering percentage of Gaillardia and Rudbeckia. Heuhera was a day-neutral plant, Rudbeckia was on obligate LD plant, and Gaillardia and Coreopsis were quantitative LD plants.

An electrophoretic study of the nine species of Coreopsis sect. Coreopsis (C. auriculata, C. basalis, C. grandiflora, C. intermedia, C. lanceolata, C. nuecensis, C. nuecensoides, C. pubescens, and C. wrightii) revealed high genetic identities (above 0.90 for most comparisons) for all species. Uniformly high identities among all taxa made it difficult to discern patterns of relationships among the species in sect. Coreopsis. Similar levels of gene diversity were found in perennial and annual species in the section, and between geographically widespread vs. more restricted species. It is suggested that the high identities result from the recent divergence among the species in sect. Coreopsis, which is viewed as a highly evolved section within North American Coreopsis. The genus Coreopsis in North America consists of 11 sections containing a total of about 44 species. The genus is distributed throughout Mexico, California, and the eastern and southeastern United States. The sections are welldefined with regard to chromosome number, morphology, and geographic distribution (Smith 1975). Attempts to produce artificial hybrids between plants of different sections have, for the most part, failed, while there is some intercompatibility and interfertility between species within sections (Smith 1975, 1976). Section Coreopsis is the largest of the North American sections. Smith (1975) viewed it as one of the most advanced groups of North American Coreopsis. The section is native to and centered within the eastern and southeastern United States, with certain species widely distributed throughout this range while others are restricted in distribution. It consists of nine species, four of which are annuals and five are perennials. Perennial species include C. pubescens Elliott, C. auriculata L., C. intermedia Sherff, C. lanceolata L., and C. grandiflora Hogg ex Sweet. The annual species are C. basalis (Dietr.) Blake, C. wrightii (A. Gray) H. M. Parker, C. nuecensoides E. B. Smith, and C. nuecensis A. Heller. The base chromosome number for the section is n = 13. Two species, C. nuecensis and C. nuecensoides, exhibit aneuploidy (n = 6, 7, 8 and n = 9, 10, 11, respectively), and one taxon, C. grandiflora var. longipes (Hook.) Torrey & A. Gray, is hexaploid (n = 39). All species are self-incompatible and presumably strongly outcrossing (Smith 1975, 1976). Discerning evolutionary relationships within the section has proven problematical. Although the section itself is a well-defined, monophyletic group, relationships among the perennial species and origin of the annual species within the section remain unclear. However, available evidence suggests that the four annual species consist of two progenitorderivative species pairs, C. basalis-C. wrightii and C. nuecensoides-C. nuecensis, the former species in each pair representing the progenitor species (Crawford and Smith 1982a, 1982b; Smith 1974; Smith and Crawford 1981). Smith (1982) constructed a phylogenetic hypothesis for the section based largely on morphology (fig. la). He suggested that C. pubescens may represent the basal taxon within the section, and that the two progenitor-derivative annual species pairs are relatively advanced, but their origin from the perennials is obscure. His phylogeny also indicates a close relationship between C. lanceolata and C. auriculata (fig. la). The cladistic analysis of North American Coreopsis by Jansen et al. (1987) agrees in many respects with Smith's proposed phylogeny, including the separation of annuals and perennials into two distinct lines (fig. lb). Annuals are composed of two pairs, namely C. basalis-C. wrightii and C. nuecensoidesC. nuecensis, in their treatment as well. However, the cladistic study differs in that C. auriculata shows closer affinities with C. pubescens rather than with C. lanceolata as suggested by Smith (1982). Preliminary chloroplast DNA data (Crawford et al. 1988; unpubl. data) suggest that C. pubescens and C. auriculata are closely allied, and that one of these taxa (or a common ancestor) could

Seventeen flavonoid glycosides were isolated from the leaves of the nine species of Coreopsis sect. Coreopsis. The compounds include two flavones, four flavonols, a 6-hydroxyflavone, a 6-hydroxyflavonol, two 6-methoxyflavones, a 6-methoxyflavonol and three chalcone-aurone pairs. Chemistry distinguishes all species except C. auriculata and C. intermedia. The mean flavonoid similarity for pair-wise comparison of the four species of annuals (C. basalis, C. nuecensis, C. nuecensoides and C. wrightii) is 0.63 whereas it is 0.66 for the five perennial species (C. auriculata, C. grandiflora, C. intermedia, C. lanceolata, C. pubescens) and 0.54 for comparison of annuals with perennials. This indicates that on the average there is slightly higher flavonoid similarity among species of annuals and among species of perennials than there is between annuals and perennials. Lack of the chalcone-aurone pair coreopsin-sulfurein in perennials is the only consistent chemical difference between annuals and perennials. Leaf flavonoid chemistry supports the hypothesis that C. nuecensis and C. nuecensoides are closely related species but flavonoid data are not concordant with the hypothesis of close relationship between C. basalis and C. wrightii, intermedia, Coreopsis pubescens and C. lanceolata are considered closely related and flavonoid chemistry is concordant with this hypothesis. Coreopsis lanceolata is also viewed as closely allied to C. auriculata, but flavonoids suggest the latter species is more similar to C. intermedia. Coreopsis grandiflora is the only perennial species lacking flavonols and has the fewest number of compounds of any species in the section; chemical data support the view that C. grandiflora is quite distinct from other perennial species of sect. Coreopsis.