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A branch from a wilting fragrant sumac tree (Rhus aromatica Aiton) in an established ornamental planting was submitted to the Plant Disease Diagnostic Laboratory in 1994. The branch exhibited dark brown streaks in the sapwood. Fusarium oxysporum Schlechtend.:Fr. was subsequently isolated from the discolored wood. To confirm pathogenicity, 2-year-old potted sumacs (0.5 to 1 m high)—fragrant, skunkbrush (R. trilobata Nutt. ex Torr. & A. Gray), smooth (R. glabra L.), and staghorn (R. typhina L.) species—were inoculated with the isolate by cutting into the bark to the xylem with a scalpel and applying approximately 0.1 ml of a 106 conidia/ml suspension into the wound. Inoculated trees were then placed on a greenhouse bench. Three trees of each species were inoculated and the experiment was repeated once. All inoculated skunkbrush and fragrant sumacs wilted and died within 3 months, whereas none of the smooth and staghorn sumacs were affected. F. oxysporum was consistently reisolated from wilted, but not healthy, trees. The host range of this isolate (FRC 0-1916) is different from that of F. oxysporum f. sp. rhois W. C. Synder, Toole, & Hepting, which was reported to be pathogenic to staghorn but not other sumac species (1). This is the first report of F. oxysporum causing wilt of fragrant and skunkbrush sumacs. Reference: (1) E. R. Toole. Phytopathology 39:754, 1949.

The host range of Leurocephala schinusae Davis & Mc Kay (Lepidoptera: Gracillariidae) was studied to assess its suitability as a biological control agent of Schinus terebinthifolius Raddi (Anacardiaceae), a serious environmental weed in the USA and elsewhere in the world. The host range was determined in the laboratory with adult no-choice oviposition (Argentina and USA) and larval development tests (USA). Seventeen plant species in ten genera were selected based on taxonomic relatedness to S. terebinthifolius, economic importance, and availability. Additional information was obtained by sampling foliage of S. terebinthifolius and six other South American native Anacardiaceae species in north-eastern Argentina. In the laboratory, except for Lithrea molleoides and Spondias mombin, all of the tested species were accepted for oviposition with a marked preference for Rhus aromatica. Incipient mines successfully developed into complete mines, pupae and adults on R. aromatica, Rhus copallinum, Schinus molle, Schinus lentiscifolius and S. terebinthifolius. In the field, although L. schinusae showed a clear preference for S. terebinthifolius, the host range, as determined by samples of host use in the native range, included three other Schinus species (S. lentiscifolius, Schinus longifolius, Schinus weinmannifolius) and one Astronium species (Astronium balansae). In conclusion, L. schinusae will not be considered for the biological control of S. terebinthifolius in continental US. However, the utilisation of this species in other infested areas such as Hawaii and Australia should be further discussed. Fil: Mc Kay, Fernando. United States Department Of Agriculture. Agricultural Research Service; Argentina Fil: Oleiro, Marina Ines. United States Department Of Agriculture. Agricultural Research Service; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Diniz Vitorino, Marcelo. Universidade Regional de Blumenau; Brasil Fil: Wheeler, Gregory. United States Department of Agriculture; Argentina

The Henry Allan Gleason Nature Preserve is located in the extensive glacial sand deposits associated with the Illinois River in central Illinois. An extensive sand dune is present within the preserve on which undisturbed dry sand prairie, disturbed dry sand prairie, and blow-out communities are present. The undisturbed sand prairie is dominated by Schizachyrium scoparium (42% of the importance value [IV]), along with Tephrosia virginiana, Opuntia humifusa, and Ambrosia psilostachya. The disturbed sand prairie is dominated by Eragrostis trichodes (24% of the IV), followed by Heterotheca camporum, Ambrosia psilostachya, and Rhus aromatica. Common species in an active blow-out includes Aristida tuberculosa and Cyperus grayioides, while nearly stabilized blow-outs have a high diversity characterized by Bouteloua hirsuta, Ambrosia psilostachya, and Eragrostis trichodes. A total of 172 plant species were found: 4 fern and fern-allies, 3 gymnosperms, 39 monocots, 126 dicots. Thirty-one non-native specie...

The avifrugivore availability hypothesis predicts that summer-fruiting species will have an extended fruiting season and slow fruit removal, and the foliar flag hypothesis predicts that fruit dispersal in autumn-fruiting species coincides with fall bird migration. Phenology of fruit removal from plants of the early summer-fruiting shrub Rhus aromatica Ait. (var. aromatica) and of the later summer-fruiting shrub Rhus glabra L. (Anacardiaceae) was studied primarily to test the avifrugivore availability and foliar flag hypotheses of fruit dispersal, respectively. Fruits of R. aromatica ripened synchronously in early June, and 77-89% of them were gone from the plants by the early July, thus failing to support the avifrugivore availability hypothesis. The pattern of rapid fruit removal in this species, which was consistent throughout a 3-year period, is in contrast with previous reports of dispersal until September and even the next summer. Display size (at both infructescence and clump levels) had no effect on removal rate in R. aromatica. Fruits of R. glabra matured in August, and about 20% of them remained undispersed the following spring. In both species, fruit removal was mostly due to dispersers rather than to natural fruit fall. No correlations were found between fruit characteristics (pulp weight, pulp-to-seed ratio, moisture content of pulp) and probability of removal during the dispersal season in either species. Browsing by mammals, most likely white-tailed deer, was responsible for the rapid removal of fruits from R. aromatica plants during the 1st week after they turned mature-red; thereafter, most fruit removal was by birds. Two removal peaks were found for R. glabra fruits: a small one in September and a large one in winter to early spring. These peaks correspond to the fall migration season for migratory birds and the scarcity of food for winter-resident birds, in the study area, respectively. Thus, the dispersal pattern of R. glabra fruits does not support the foliar flag hypothesis.Key words: avifrugivore availability hypothesis, foliar flag hypothesis, fruit characteristics, fruit dispersal by birds or mammals, fruiting phenology, Rhus aromatica, Rhus glabra.

Anatomy of the endocarp was studied in relation to the physical dormancy-breaking mechanisms in experimentally treated Rhus aromatica var. aromatica and R. glabra germination units, which include seed plus endocarp (hereafter seeds). The endocarp has three distinct layers, with brachysclereids on the outside, osteosclereids in the middle, and macrosclereids on the inside. Brachysclereids in the carpellary micropyle region (i.e., region immediately adjacent to the integumentary micropyle) are shorter than those in other parts of the endocarp, and the macrosclereids in this region are not elongated. Thus, a weak point is formed in the endocarp. Concentrated sulfuric acid broke seed dormancy in R. aromatica by eroding the brachysclereids and osteosclereids in the carpellary micropyle region, whereas boiling water broke dormancy in seeds of R. glabra by inducing a blister adjacent to the carpellary micropyle.

Soil seed bank dynamics, greenhouse seed germination and field seedling survival were compared in the weakly-clonal shrub Rhus aromatica Ait. and the strongly clonal shrub R. glabra L. (Anacardiaceae). Although both species had persistent soil seed banks, their sizes and dynamics differed greatly. The high seed density (5668 ± 1267 m−2 to 8739 ± 3303 m−2) in R. glabra was depleted by ca. 5% annually and replenished with 1102 ± 316 to 1828 ± 486 seeds m−2, whereas the low seed density (9 ± 5 to 138 ± 68 m−2) in R. aromatica was depleted by ca. 50% annually and replenished with 37 ± 7 to 69 ± 18 seeds m−2. Seeds of both species germinated within established populations. However, recruitment from seedlings was successful in R. aromatica but not in R. glabra, which depended exclusively on root suckering for aboveground population increase. This difference in local recruitment modes between the two species was correlated with differences in soil seed bank dynamics and other life history traits, such a...

Morphology and physiology of fruit and seed development were compared in Rhus aromatica and R. glabra (Anacardiaceae), both of which produce drupes with water-impermeable endocarps. Phenology of flowering/fruiting of the two species at the study site was separated by ;2 mo. However, they were similar in the timetable and pattern of fruit and seed development; it took ; 2m o and;1.5 mo for flowers of Rhus aromatica and R. glabra, respectively, to develop into mature drupes. The single sigmoidal growth curve for increase in fruit size and in dry mass of these two species differs from the double-sigmoidal one described for typical commercial drupes such as peach and plum. Order of attainment of maximum size was fruit and endocarp (same time), seed coat, and embryo. By the time fruits turned red, the embryo had reached full size and become germinable; moisture content of seed plus endocarp had decreased to ;40%. The endocarp was the last fruit component to reach physiological maturity, which coincided with development of its impermeability and a seed plus endocarp moisture content of ,10%. At this time, ;50, 37, and 13% of the dry mass of the drupe was allocated to the exocarp plus mesocarp unit, endocarp, and seed, respectively. The time course of fruit and seed development in these two species is much faster than that reported for other Anacardiaceae, including Rhus lancea, Protorhus,and Pistacia.

Premise of the study: Microsatellite markers were developed for Spondias radlkoferi to assess the impact of primate seed dispersal on the genetic diversity and structure of this important tree species of Anacardiaceae. Methods and Results: Fourteen polymorphic loci were isolated from S. radlkoferi through 454 GS-FLX Titanium pyrosequencing of genomic DNA. The number of alleles ranged from three to 12. The observed and expected heterozygosities ranged from 0.382 to 1.00 and from 0.353 to 0.733, respectively. The amplification was also successful in S. mombin and two genera of Anacardiaceae: Rhus aromatica and Toxicodendron radicans. Conclusions: These microsatellite loci will be useful to assess the genetic diversity and population structure of S. radlkoferi and related species, and will allow us to investigate the effects of seed dispersal by spider monkeys (Ateles geoffroyi) on the genetic structure and diversity of S. radlkoferi populations in a fragmented rainforest.

Effect of cutting age (weeks after budbreak) and K-IBA concentration on percent rooting of Mexican redbud (Cercis canadensis var. mexicana (Rose) M. Hop- kins), larchleaf goldenweed (Ericameria laricifolia (Gray) Shinners), littleleaf ash (Frax- inus greggii Gray), and evergreen sumac (Rhus virens Gray) were investigated. For cuttings treated with K-IBA, maximum predicted percent rooting from regression analysis was 88% for cuttings of Mexican redbud taken 4 weeks after budbreak and treated with 21 g·liter -1 , 99% for larchleaf goldenweed taken 6 weeks after budbreak and treated with 16 g·liter -1 , 86%, for littleleaf ash taken 16 weeks after budbreak and treated with 17 g·liter -1 , and 24% for cuttings of evergreen sumac taken 16 weeks after budbreak and treated With 5 g·liter -1 . Chemical names used: potassium salt of 1H-indole-3-butanoic acid (K-IBA). Mexican redbud, larchleaf goldenweed, littleleaf ash, and evergreen sumac are southwestern shrubs with potential as adapted ornamental for the area (Duffield and Jones, 1981; Miller, 1978; Nokes, 1986). Germ- plasm collections of all four species exhibit variability in floral color (Mexican redbud) or growth habit (larchleaf goldenweed, lit- tleleaf ash, evergreen sumac) that could be exploited through vegetative propagation to provide superior plants. I found no reports regarding rooting of stem cuttings of these species, but studies on related species indi- cate timing and IBA concentration are crit- ical. Despite an early report that nontreated stem cuttings of eastern redbud (Cercis can- adensis L.) taken in June and July rooted 75% to 90% in 4 weeks (Thomas, 1936), other authors report little success in rooting softwood or semi-hardwood cuttings (Dirr and Heuser, 1987; Hartmann and Kester, 1975; Nokes, 1986). Ashes (Fraxinus spp.) are considered very difficult to propagate from stem cuttings (Dirr and Heuser, 1987). One percent of softwood cuttings of fragrant ash (Fraxinus cuspidata Torrey) treated with an auxin-tale preparation of 0.8g IBA/g rooted (B.J. Simpson, personal communication). Softwood and semi-hardwood cuttings of fragrant sumac (Rhus aromatica Ait.), a de- ciduous species, rooted after treatment with IBA at 1 g·liter -1

both species originated from the inner epidermis of the ovary wall. At anthesis, the proto-endocarp was 3layered; one and two weeks after anthesis in R. glabra and R. aromatica, respectively, it had become distinctively 4-layered, and the innermost layer had elongated 5-10 times. Five weeks after anthesis in R. aromatica but only three weeks after anthesis in R. glabra, all layers except the outermost crystalliferous one were fully elongated and had begun to lignify. In both species, the crystalliferous layer remained parenchymatous, did not elongate, and contained crystals. The similarities in ontogeny and anatomy of the pericarp in these two species support the opinion that Lobadium should be kept as a subgenus within Rhus, rather than being elevated to the generic level. However, more taxa of Rhus need to be studied before the taxonomy of the genus can be clarified.

The Grand Bend succession can be divided into three periods: a colonizing stage, up to 1600 years; a transition period from 1600 to 2900 years; and a persistent stage from 2900 to at least 4800 years. The colonizing stage is dominated by grasses, Juniperus spp. and Quercus prinoides. Transition begins when persistent species invade at certain points; the earliest species are usually Quercus velutina × rubra, Rhus aromatica, and Prunus virginiana. During the transitional period the patches of persistent vegetation grow until they coalesce. This marks the inception of the persistent stage during which the vegetation cover is predominantly oak–pine forest. Hence the path of succession does not differ from point to point but the rate of succession does. It is argued that the existence of distinct successional stages and the mode of transition between them support the organismal concept of vegetation.

Schmaltzia serotina was described in 1905 by Greene. Palmer and Steyermark (1935) reduced S. serotina to a variety of Rhus canadensis Marsh., non Mill. (=R. aromatica Ait.). Barkley (1937), in his monographic treatment of Rhus in North and Central America, transferred var. serotina to the essentially western R. trilobata Nutt. This shift was based not only on morphological differences, but also on the fact that R. aromatica flowers primarily prior to leaf development, whereas var. serotina flowers after leaf development. Although more critical observations are needed on this point, the western R. trilobata sometimes flowers before and sometimes during leaf development. Fernald (1941, p. 599-602) promptly disagreed with Barkley's treatment and presented arguments contending that both var. serotina and var. arenaria belong in the Rhus aromatica complex. His arguments were based on fruit pubescence, "stone" size and shape, abaxially glabrous floral bracts, and the size of the terminal leaflet. He held that the densely pubescent twigs were not a trait of sufficient significance. The four current eastern manuals of Fernald (1950), Gleason (1952), Steyermark (1963), and Gleason and Cronquist (1963) have all treated var. serotina as part of R. aromatica. While attempting to identify specimens of the local flora, we have become aware of these two similar, yet quite distinct, taxa growing in adjacent niches, but so close that at times their branches overlap. Over a period of six years this population has been observed and one taxon has always been found to flower some time after the other has set fruit. Phenology data, kept for the past four years, has shown that the two taxa involved are at their peak of flowering about three weeks apart. In 1964 the early flowering Rhus aromatica var. aromatica first flowered April 4 and reached its peak of flowering April 14. The first flowers of the other taxon, R. trilobata var. serotina, appeared April 27, when the leaves were half grown, and the plants were in full flower by May 4 (Fig. 1). Rhus aromatica var. aromatica in central Missouri is an undershrub that occupies the broken woodland slopes, while R. trilobata var. serotina is found only on rocky outcrops, commonly on steep bluffs, with its roots in the rock crevices, a very xeric site in a mesic deciduous woodland. On the sites observed we have not found any indication of hybridization between the two taxa. This suggests that they are genetically isolated. Examination of seeds of Rhus trilobata from California and New Mexico has revealed that they are, in many instances, as small or smaller than those of R. aromatica, an indication that seed (stone) size is of no particular value in the separation of the two taxa (Table 1). California, Colorado, and New Mexico material of R. trilobata has fruits which are both pilose and glandular viscid as well as having a pruinose covering. The pubescence of the fruit is rather easily rubbed off, an accident which may have happened to the specimens Fernald examined. We have seen two collections of R. trilobata var. trilobata fromn Kansas, however, in which the pilose hairs were very sparse, suggesting that this also is a variable character. In Missouri, the ecology of R. trilobata var. serotina is fully compatible with it being considered as an eastern extension of the western R. trilobata. An additional bit of evidence suggesting such a relationship may be noted by comparing the

One of the most unusual habitats in which to find ferns is the formation of limestone of Silurian Age upon which cedar barrens develop in Kentucky. Recently the author had occasion to study and collect the plants and ferns found on two of these outcroppings-one in Bullitt County, near Cedar Grove-the other, in Nelson County, near Bardstown, along Cedar Creek. The flora on these barrens is distinctive and alike on both. The actual barren is made up of a grayish clay which is very slippery when wet, yet hard and brittle when dry, cracking to a depth of about a centimeter. This area is open and barren, having only occasional patches of Rhamnus lanceolata and Rhus aromatica, with an infrequent Celtis bush and cedar tree. Peeking out from under this shrubbery are delicate Shooting Stars (Dodecatheon meadia), pale blue Sisyrinchium angustifolium, white Nothoscordum bivalve, little Scutellaria parvula, and bright yellow-orange Lithospermum canescens. So it is in May. Later in the season, in August, the flora is quite different, the predominating species being Agave virginica, Sabatia angularis and its white form, several Rudbeckias, Echinacea pallida, Ratibida pinnata, Petalostemon candidum, Thalictrum revolutum, Asclepias verticillata, A. tuberosa and Acerates viridiflora. Just back of this barren is a sort of transition zone of mesophytic woods containing chestnut-oaks, hackberry, and sassafras, canopying a humus-containing soil in which Frasera caroliniana grows, along with Botrychium virginianum and Asplenium platyneuron. Back in this wooded area is an outcropping of Silurian limestone, 53