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ABSTACT Irrigated plots of a mixed sward of four grasses and white clover were cut to a height of 3 cm in either June, August, October, December or February. The plots cut at each commencement date were harvested when the height of growth of the pasture was either 10, 18, 25, 32, 40, 48 or 55 cm. At each harvest, the pasture was cut at 7 to 8 cm intervals down to a height of 3 cm. DM production, botanical composition, in vitro digestibility (DOM) and CP of each layer was determined. DM production declined from the lower to the upper layers for pastures shorter than 32 cm. For pastures taller than 32 cm, DM production declined from the lower to the middle layers, then increased in the upper layers, due mainly to the presence of seed heads. Maximum percentages of DOM and CP were observed for the middle layers of the pastures taller than 25 cm. For pastures shorter than 25 cm, DOM and CP percentages increased from the lower to the upper layers, for all commencement dates. The percentages of DOM and CP of each layer decreased as the height of growth increased. The percentage of DOM showed a positive correlation with the percentages of Lolium perenne, Bromus unioloides and Trifolium repens, and a negative correlation with the percentages of Paspalum dilatatum and chlorotic material. The percentage of CP showed a positive correlation with the percentages of Paspalum dilatatum, Dactylis glomerata and Trifolium repens and a negative correlation with the percentages of chlorotic material and the total of the four grasses within the pasture layers. The lower layers of the pasture produced large quantities of DM and, despite the lower in vitro digestibility of these layers, they produced more DOM than the other pasture layers. The DOM production of the pasture increased with increasing height of growth, but decreased as the commencement date was altered from winter through to the end of summer.

Irrigated plots of a mixed sward of Lolium perenne, Paspalum dilatatum, Bromus unioloides, Dactylis glomerata and Trifolium repens were used in 2 experiments during 4 years. In the first experiment, die treatments comprised factorial combinations of heights of cutting of 3, 6 and 10 cm (1.2, 2.4 and 3.9 in.) above ground level, and heights of growth of 5, 13 and 20 cm (20, 5.1 and 8.0 in.) above the height of cutting. In the second experiment, 8 combinations of dose (3 cm or 1.2 in.) or lax (10 cm or 3.9 in.) cutting were applied at various times during each year. In the first experiment, DM production for cutting heights of 3, 6 and 10 cm was 50, 44 and 43 t/ha (198,17.5 and 171 ton/ac), respectively; the DOM production was 37, 32 and 32 t/ha (147, 12.7 and 12.7 ton/ac). DM production for growth heights of 5, 13 and 20 cm was 45, 46 and 48 t/ha (17.9, 183 and 191 ton/ac), respectively. DOM production, 34 t/ha (13.5 ton/ac), was not affected by height of growth. Percentages of protein (26, 22 and 20) and DOM (76, 72 and 71) declined as the height of growth was increased; but cutting height produced no significant effects in them. As cutting height was increased the percentage of clover declined (40, 31 and 23) and that of grasses increased (52, 66 and 72); diere were smaller changes with changes in height of growth. Hie second experiment showed that the difference between close and lax cutting became significant only when lax cutting was applied for at least half of the cuts each year. DM production was similar for treatments witii the same number of close or lax cuts, regardless of the time of year at which the two heights of cutting were applied.

Seed fertility index measured by seed set under bags was studied in a diallel cross of 10 selected smooth bromegrass (Bromus inermisLeyss) plants. Specific combining ability had the most influence on fertility percentage, followed by the environmental effect. The influence of general combining ability was quite low.

I have shown in previous publications that the parasitic Uredine Puccinia dispersa , growing on grasses of the genus Bromus , is usually very closely adapted to the species of host-plant selected: that although no morphological differences can be detected between the fungus as met with on different species of Bromus —A, B, C, &c.—it by no means follows that spores from the parasite, as found growing on A, will infect B or C, or that spores from the fungus as reared on B or C will infect the species A.

The types and distribution of silica bodies (opaline phytoliths) of 26 species of native and introduced grasses of the range grasslands of southern Alberta are described. The genera examined are Bromus, Festuca, Poa, Koeleria, Deschampsia, Calamagrostis, Phleum, Agropyron, Elymus, Stipa, Danthonia, and Bouteloua. Scale drawings of representative silica bodies for each genus are provided.The observations are discussed in relation to grass taxonomy, and to the overall role of silica in grasses.

Immunoelectrophoretic studies of the seed proteins of material provisionally referred to B. secalinus var. or f. hirsutus have revealed that it is serologically distinct from B. secalinus. The plant has many of the characters of B. secalinus fitting that species to life as a contaminant of cereal fields, but the floret and seed sizes are much smaller, and the sheaths are normally hairy. In Britain the plant appears to contaminate small-seeded pasture grasses which are sown on roadsides. The chromosome number of this plant is 2n = 14, unlike typical B. secalinus which has 2n = 28. The plant seems to be introduced in Britain, but its native distribution is not known. In view of its distinctive morphology and its serological difference from B. secalinus and other bromes, it is proposed to name it as a new species: Bromus pseudosecalinus P. SMITH sp. nov.

Various lucerne (Medicago sativa L.) /grass associations were compared with lucerne sown alone over a three-year period on high-fertility soil at Invermay Research Station. Companion grasses induded cocksfoot (Dactylis glomerata L.). timothy (Phleum pratense L.), perennial ryegrass (Lolium perenne L.), short-rotation ryegrass (Lolium perenne × L. multiflorum). phalaris (Phalaris tuberosa L.), meadow fescue (Festuca pratensis Huds.), tall fescue (Festuca arundinacea Schreb.), and prairie grass (Bromus catharticus Vahl.). All mixtures out-yielded lucerne sown alone in the first year, but differe:1ces in yield were small thereafter. The inclusion of a companion grass helped to control weeds except in the phalaris treatment. Although all the grasses had some merit, cocksfoot and tall fescue were considered superior to the others. Mixtures of lucerne with cocksfoot and tall fescue were more productive in winter than lucerne alone, weed control was good, and the balance of lucerne and grass was satisfa...

ONE OF the commonest, most widespread, and variable groups of grass species in western North America is the subgenus Ceratochloa of the genus Bromus, of which the best known species native to the United States are B. carinatus H. & A. and B. marginatus Nees. The problem of the number of species actually present in this group has been a constant puzzle to systematists, as is evident from the discussion of Hitchcock (1935, p. 38). In this manual he recognizes four native species of Ceratochloa, but the list of synonyms under the various species names (op. cit., pp. 811-817) indicates that fourteen different species have been described by various authors. Cytologically, the great bulk of the forms are octoploids, with 2n 56 (Stebbins and Love, 1941), but hexaploid (2n = 42) and decaploid (2n 70) counts have been recorded (Stiihlin, 1929; Nielsen and Humphrey, 1937; Nielsen, 1939), while there is one doubtful record of a diploid form (Stiihlin, 1929). In an attempt to secure this purported diploid, the senior author obtained seed of B. carinatus from Stiihlin's source, the Munich Botanical Garden, but the strain received was a typical octoploid. In view of the evidence presented below as to the probable origin of the B. carinatus complex, the presence of a diploid in this complex seems highly unlikely. In addition to its interest from the systematic standpoint, this complex contains forms of considerable forage value (Hitchcock, 1935, p. 33; Sampson and Chase, 1927, pp. 21-22). B. marginatus has been recommended by Stewart, Walker, and Price (1939) for reseeding range lands of the intermountain region. Among a large series of grass species sown in experimental range plots throughout California, B. carinatus has proved, one of the most readily established of any species native to the state (Burle Jones, unpublished data). Therefore, hybrids between different forms of this complex might be of value both as an aid to understanding the species problem as it relates to this group, and as a source of new varieties for establishment on range lands. For the latter purpose another series of hybrids was considered promising-between the B. carinatus complex and an eVen more valuable forage grass belonging to the section Ceratochloa, the South American B. catharticus Vahl. (= B. unioloides HBK, cf. Hitchcock, 1935). The work reported in the present paper, however, has shown that these latter hybrids are of more interest from the phylogenetic and systematic than from the agronomic point of view. MATERIAL AND METHODS.-The strains used in the present hybridization experiments are part of a large collection assembled by the senior author and

Seedlings of 286 varieties or strains of various species belonging to Trib. Hordeeae (Agropyrot2, Elylnus, Hordeum, Triticum, Aegilops, Aegilotricum., Lolium), Bromeae (Bromus) and Agrosteae (Aue;ea and Holcus) including 105 strains of cultivated oats were tested with Puccilcia coroleata CORDA f. sp. Avenae 231. The experimental results are summarized as follows : 1) 10 species of Agropyron, 5 species of Elymus, 15 species of Triticum, 5 selections of Aegilotricum, 2 selections of Agrotricum, 2 species of Lolium, 17 species of Bro, , tus and I species of Holcus were found to be highly resistant or immu.ne to Puccinia coronata f. sp. Avenae 231. 2) Among 36 varieties or strains of 9 species of Hordeum, I strain of Hordeum agriocrithon var. eu-agriocrithon, I strain of H. Gussoneanum, 4 varieties or strains of H. spo, etaneum and two varieties or strains of H. vulgare were resistant (Infection type 1), while the other were highly resistant' or immune.

Several factors, singly or synergistically, may influence the behavior of weedy species under conditions of intraspecific competition. The species studied were Brownals inermis, B. tectorum, Capsella bursa-pastoris, Conysa canadensis, Plantago lanceolata, P. major, Se7tecio sylvaticuts, S. viscosus, and Silene acnglica. Some or all of the species were subjected to condi- tions of intraspecific competition involving variable regimes of: (1) seed-sowing density, (2) soil surface, (3) fertilizer, (4) moisture, and (5) habitat, i.e., greenhouse and non-greenlhouse (onditions. Initially the vegetative dry weight production per unit area increased as density in- creased for every species. After a certain density (relative to the species) was reached, produc- tion was independent of density. All species displayed considerable plasticity in that similar geno- types showed a great increase in seed production between high and low densities (e.g., over a 100-fold increase for Capsella bursa-pastoris). Mean seed weight was constant under variable con(litions of density, fertilizer, soil surface, and moisture in all species except Bromus tectorum. In nmixed stands, the population of each species is smaller than its potential maximum. The size of a population of seedlings may be determined by the number of microenvironments suitable for germination ("safe-sites") in an area. The populations of the respective species may bc further regulated by: (1) self-controlled germination (Bromus inlermis, ConyZa cana- densis, Plantago lanzceolata, and Silene anglica) ; (2) mortality (Plantago major); and (3) individual plasticity (Bromus tectorum, Capsella bursa-pastoris, Senecio sylvaticus, and S. viscosus).

A study was made of the distribution of Puccinia glumarum (Schm.) Erikss. and Henn. in Canada, its specialization, host range, and reaction to environmental conditions. Unlike Puccinia graminis Pers., this rust has a limited distribution, being confined to British Columbia, Alberta, and the western half of Saskatchewan. The natural hosts include a number of native grasses, particularly Hordeum jubatum L. and certain species of Agropyron, Elymus, and Bromus. Wheat and barley also become infected although to a rather limited extent: Stripe rust collected on the above-mentioned hosts has been studied in the greenhouse and has in all cases shown ability to attack wheat varieties. In all instances where identification of physiologic forms was carried out the rust strains were classified as either form 8 or form 13 of wheat stripe rust, the latter form being the more common. The fact that the present authors have collected known physiologic forms of wheat stripe rust on species of Hordeum, Elymus and Agropyron, and have shown that forms 4, 6, 8 and 13 can attack seedling plants of Hordeum, Agropyron, and Elymus species throw a doubt on the existence of the Hordei, Elymi, and Agropyri varieties created by Eriksson.Greenhouse studies showed that P glumarum is extremely sensitive to environmental conditions, particularly temperature. The optimum for uredospore germination is 10° to 12 °C., and for rust development 13° to 16 °C. Varieties susceptible at from 10° to 16 °C. developed resistance at higher temperatures, becoming extremely resistant at 25 °C. On account of the sensitiveness of this rust to high temperatures it seems improbable that it will ever become thoroughly established in Manitoba and Saskatchewan, as in these two provinces the summer temperature is probably too high to permit its development.

Nonporous wax crusts were used to compare seedling emergence of tall wheatgrass (Agropyrun elongatum Host), pubescent wheatgrass [Agropyron trichophorum (Link) Richt.], basin wildrye (Elymus cinereus Scribn. and Merr.), Russian wildrye (Elymus junceus Fisch.), tall fescue (Festuca arundinacea Schreb.) and smooth bromegrass (Bromus inermus Leyss.). Seedlings were grown at O, −2.3, −4.4, −6.7, and −8.4 bars osmotic potential under soft, medium, and hard wax crusts, 3 mm thick. The treatments were designed to simulate the separate and combined effects of salty soils and crusts as limiting factors in seedling establishment in arid regions. The germination and emergence phases were separated by using only seeds that germinated as a basis for percent emergence. Emergence of all six species was lower under hard crust than under soft wax crust. Pubescent wheatgrass and smooth bromegrass were most affected by the crust hardness. In the range of osmotic potential used, there was no reduction in emergence as osmotic potential was reduced when the emergence was taken at 2 weeks; however, reduction in osmotic potential did delay emergence. The delay was slightly longer for hard crust than for soft crust. Although osmotic potential did not reduce emergence under soft crusts, a combination of low osmotic potential and hard crust did reduce the emergence of tall wheatgrass, basin wildrye, and Russian wildrye. The emergence of pubescent wheatgrass smooth bromegrass, and tall fescue was reduced principally by the hardness of the crust. Tall fescue was least able to penetrate the crust. The results indicate that osmotic potential may be less important in reducing emergence of field seedlings than is the presence of a crust. In a field situation the slower rate of emergence and low osmotic potential may involve additional crust strength as the soil surface dries.

A previously unreported member of the section Bromopsis, having taxonomic similarities to B. pumpellianus and B. pacificus, was recently found in westcentral Alaska. Its relationship to these species and to B. inermis and B. ciliatus has been investigated. Both this unreported member (Bromus X) and B. pacificus were shown for the first time to be tetraploids (2n = 28); forms of B. ciliatus originating in Russia and North America were diploids (2n = 14); and a number of Alaskan B. pumpellianus were octoploids (2n = 56). Chromosomes with large satellites were found in Bromus X, B. pumpellianus, and a tetraploid form of B. inermis but not in B. pacificus or B. ciliatus. Seed was produced and hybrids resulted from crosses of Bromus X with B. pumpellianus and tetraploid B. inermis but no seed developed from crosses with B. pacificus and B. ciliatus. A relatively high frequency of stainable pollen among the hybrids suggested that they were partially fertile. It was concluded that Bromus X was a very close relative of B. pumpellianus and B. inermis but was not closely related to B. pacificus or B. ciliatus.

Twelve lines of prairie grass (Bromus unioloides H.B.K.), most of them selected for high yield of foliage, were measured for concentrations of 15 major and minor elements in the harvest of foliage taken during spring growth. Significant differences (about twofold) between lines were obtained in the concentrations of sodium, calcium, magnesium, sulphur, phosphorus, iron, manganese, zinc, iodine, and silicon, but not for potassium, chlorine, total nitrogen, nitrate-nitrogen, and copper. A significance test was not obtained for selenium. There were significant negative regressions of element concentration, on dry weight of foliage harvested, for calcium, magnesium, total nitrogen, and phosphorus. When the 12 populations were compared for total amounts of these elements present in the harvested foliage, they differed significantly only for sodium and phosphorus. The organic anion content, as measured by the total cation minus anion content for the major inorganic elements, was very low in all lines. ...

Eight seed lines of prairie grass (Bromus unioloides H.B.K.) grown in pots were compared at three cutting severities in each of three soil types. Significant differences in dry herbage production between lines were obtained in all treatments except those in the most productive soil. Of the other characters measured—leaf length, leaf width, number of tillers and leaves per tiller—leaf length was most closely indicative of herbage weight differences, in all treatments. Although certain lines could be identified as generally adaptable, that is, consistently good or bad performers in all treatments, no significant differences between lines were found for specific adaptability to increasingly productive soil or to cutting treatments.

Summary Periodicity of germination was studied in 26 species of grasses. Considerable variation from species to species was found in rapidity of germination, seasonal periodicity of germination, and length of time during which seed remained viable in the soil. The following are examples of species showing: (a) no dormancy–Hordeum murinum and Echinochloa crus-galli var. frumentacea; (b) some dormancy—Festuca rubra var. commutata and Bromus mollis; and (c) definite dormancy—Agrostis temnuis and Glyceria fluitans. The results are discussed from the viewpoints of: (a) control of weed grasses; and (b) contamination of seed crops by buried viable seeds.

Seed lines of 52 Bromus species introduced from many countries were grown and compared at Palmerston North. There were significant differences among the five taxonomic sections of Bromus for each character studied. Bromopsis and Ceratochloa species were generally few-tillering and sparsely-heading compared with the species from Neobromus, Eubromus, and Bromium, but were more persistent in summer. Tiller size and plant habit did not relate closely to the characters above. For all characters there was significant variation among the species within each section but in many cases this range of variation was covered by the different lines of a single species. The results are discussed with regard to obtaining Bromus material for use in New Zealand pastures.

Many overwintering cultivated and native plants proved susceptible to the low-temperature basidiomycete which causes winter crown rot or snow mold of forage legumes and grasses in Alberta. Tests were made by inoculation in the late fall, or by planting in infested land. In the legumes, high resistance was found only in Medicago falcata and a Siberian strain of Trifolium pratense. T. hybridum, Melilotus spp., and the commonly grown varieties of alfalfa were particularly susceptible. Bromus spp. and Agropyron spp. proved highly resistant. Resistance was moderate in Elymus spp., Poa pratensis, and Festuca elatior; and slight in F. rubra and Phleum pratense. Agrostis alba, winter wheat, and winter rye were highly susceptible. In tests on horticultural plants, rhubarb and chives appeared to be immune; raspberry, peony, and columbine were resistant; and strawberry, parsnip, iris, and tulip were highly susceptible. A wide range of native plants and weeds suffered severe damage, and only Thalictrum spp. proved highly resistant. Shrubs and trees were not attacked.Following severe damage, crop rotation proved to be essential for the control of winter crown rot. The pathogen did not persist in the soil to any extent for longer than two to three years in land which was summer-fallowed or planted to annual crops or resistant grasses. Brome and other resistant grasses proved helpful in maintaining forage stands. Fertilizer treatments did not reduce the damage. Uncut tops and debris favored spread of the disease in alfalfa stands.

Seed lines of prairie grass (Bromus unioloides H.B.K.) collected overseas and throughout New Zealand were compared for some growth characters at Kaikohe, Palmerston North, Lincoln, and Gore. There was a large range among lines, and especially among overseas lines, in plant habit, yield, earliness of heading, and resistance to head smut. Within the New Zealand collection lines obtained from pastures were on the average less erect, slightly more producti.Je, later to begin heading, and more resistant to Head smut than were lines from ungrazed sites. Commercial lines tended to be of the pasture type, except in yield. There was a significant negative correlation between susceptibility to head smut of a line and its spring yield. and also between earliness to head of a line and its latitude of origin in New Zealand. Overseas lines generally yielded well at Palmerston North, moderately at Gore, but poorly at Kaikohe. The highest yielding New Zealand lines at all three stations were those collected from...

Dormant and nondormant rescuegrass (Bromus catharticus Vahl.) seed were tested on the two-way thermogradient plate to make a comprehensive comparison of their germination responses to alternating and constant temperatures within a range of 5 to 35 C. Nondormant seed germinated within 1 week at a constant temperature near 30 C and within 4 weeks over most of the temperatures above 15 C. Dormant seed did not germinate at constant temperatures. Moderate germination of dormant seeds was obtained at 4 weeks with alternating temperatures. Imbibition of dormant seed on 0.2% KNO₃-moistened blotters improved germination slightly. Clipping off the distal end of the caryopsis of dormant seed produced substantial germination at 3 weeks, but only at alternating temperatures. The combination of KNO₃ and clipping resulted in a germination response by dormant seed at almost the same temperature range favorable for germinating nondormant seed.

The material collected by G. W. Fischer and the writer in the Southwest in late summer of 1957 has been discussed in part in the last paper in this series (17), but there proved to be too much noteworthy material in the 1957 collections to include all of it one issue of a periodical. Besides reports of noteworthy specimens collected by my colleagues and myself I have included a few specimens obtained from mounted sheets of grasses filed in the Department of Botany Herbarium, Washington State University, Pullman. Earlier I reported on about 130 specimens removed from grasses arranged alphabetically partly through the genus Bromus (15). The additions from this source include only through Bromus sitchensis Trin. The bulk of the phanerogamic specimen sheets remain unexamined. Because available time has not permitted any substantial study of this backlog, the writer prefers to include the small amount of additional data in the body of the current paper.

The taxonomy of the genus Bromus section Bromopsis in Alaska is summarized. With recent changes incorporated in the treatment the section now includes B. ciliatus (2n = 14), B. richardsonii (2n = 28), B. pacificus (2n = 28), B. pumpellianus ssp. pumpellianus (2n = 56), and B. pumpellianus ssp. dicksonii (2n = 28), all indigenous, and B. inermis (2n = 56), an introduction. A taxonomic key, species descriptions, and comments are provided along with generalized distribution maps of the indigenous taxa.

The potential and proven disease resistance of various cool season cultivars of common forage, range, and turfgrasses to fungi, bacteria, and viruses is reviewed. Included are certain grass species ofAgropyron, Agrostis, Arrhenatherum, Bromus, Dactylis, Elymus, Festuca, Lolium, Phalaris, Phleum, andPoa. These cultivars may be useful in crop improvement programs and for germplasm exchange.

The evolutionary effects of outbreeding and inbreeding systems have caused considerable interest and speculation over the years and their influence in changing gene frequencies has been formalized mathematically (see Fisher, 1949; Wright, 1921). A large body of data is available on the genetical basis of the sex and incompatibility mechanisms promoting outcrossing in plants but similar information on the devices favoring self-fertilization is much more scanty. Self-pollinating races or species occur widely throughout the angiosperms and there seems little doubt that they have been derived from outcrossing relatives (Stebbins, 1957). In self-compatible plants, self-pollination is often limited either by temporal or physical separation of the mature anther and stigma or by some combination of these two types of mechanism. Automatic self-pollination is effected by the juxtaposition of the mature anther and stigma. It can be the result of regular environmental changes as in Viola (Evans, 1956; Bergstrom, 1939; Bergdolt, 1932) where open, cross-pollinated flowers occur early in the season and cleistogamous flowers are produced during the longer, warmer days of summer; a comparable seasonal sequence occurs in Bromus carinatus (Harlan, 1945). Self-fertilization may also result from temporary or local environmental changes as in Narthecium ossifragum, Stipa, and Danthonia (Stebbins, 1957). In the majority of self-pollinating plants, however, the mechanism is apparently less subject to environmental influences. Stebbins (1950, pp. 176-179) has suggested that self-pollination is most likely to arise

Populations of the California vole, Microtus californicus , were followed at two sites near San Francisco Bay in order to investigate changes in diet and condition of these cycling microtine rodents. Mark and recapture analyses provided information on condition during seasonal (season to season) and annual (year to year) fluctuations, and snap trapping provided stomach samples for dietary analyses and carcasses for determinations of reproductive condition and fat reserves. Seasonal changes in condition were found to be correlated with dietary changes. The end of the breeding season in late spring was associated with low growth rates, low survival rates, and low fat reserves. At the same time the vegetation was drying, and the diet changed from one dominated by grass stems and leaves to one dominated by grass seeds. Breeding and adult growth sometimes began before the autumn rains while grass seeds were still the major dietary item, but occasional meals of green forbs and perennial grass were also taken at this time. Three annual grasses, Lolium multiflorum, Avena fatua , and Bromus rigidus , were preferred foods and formed the bulk of the winter diet at both low and high populations. The standing crop and seed production of these grasses were severely reduced by high vole populations. Reduction in food availability and quality might have caused the delay in the start of the breeding season, the low fat reserves and the continued population decline that were observed after the peak population. These results indicated that nutritive factors could be involved in microtine population cycles at low latitudes and point to the need for further research on diet quality and nutritional physiology of Microtus .

The protein and RNA of bromegrass mosaic virus were separated from each other by dialysis of the virus against 1 M -calcium chloride. In this medium the virus is degraded, the RNA is quantitatively precipitated and there remains a supernatant solution of viral protein. The protein obtained in this way was soluble in various buffers in the pH range 5·5 to 6·5 and exhibited a single symmetrical sedimenting boundary in the ultracentrifuge. Its molecular weight was 40,000 ± 2,000 as determined by the Ehrenberg method of approach to sedimentation equilibrium. Amino acid analyses indicated that there were about 52 lysyl plus arginyl residues per molecular weight of 40,000. Tryptic hydrolysis of urea-denatured protein yielded 23 soluble peptides and an insoluble residue amounting to about 20% by weight of the intact protein. From the number of soluble tryptic peptides and an assumed number of tryptic peptides in the insoluble residue it was concluded that the molecular weight of the protein subunit of bromegrass mosaic virus was slightly greater than 20,000 and that the protein moiety obtained by treatment with 1 M -CaCl 2 was a relatively stable dimer of the subunit. Partial separation of the soluble peptides resulting from tryptic hydrolysis was achieved on a preparative scale by column chromatography.

Results of chemical analyses of wheat germ and of barley endosperm indicate that, while the germ preparation can yield typical pectic materials, including a pure araban, such materials are absent from the central endosperm. The behaviour of sections of seeds of various grasses in a number of different solvents indicates that in all samples examined of Bromus sterilis, and in some samples of barley, intercellular cementing material is either lacking or else very readily soluble in water, whereas in all samples examined of Bromus mollis and in other samples of barley, proteinaceous material is present between the individual cells of the endosperm.

Serological techniques have been used to compare the seed albumin and globulin fractions of species of Bromus L. and Boissiera squarrosa (Soland.) Nevski. Compared with other grass genera, Boissiera squarrosa gives a very strong reaction with Bromus antisera, resembling the reactions of Bromus section Bromus species. It is considered that this evidence of serological relationship, together with evident morphological resemblance and the same basic chromosome number, require the transference of the species to the genus Bromus. It is therefore included in that genus under the name Bromus pumilio (Trin.) P. Smith, comb. nov. The significance of reactions with Bromus antisera by seed extracts of species in the tribe Hordeae is discussed.

Functional and floristic properties of annual grasslands on serpentine and sandstone soils at an elevation of 180 m on Stanford University's Jasper Ridge were determined along an intuitive habitat gradient from northeast to southwest exposures. The most frequent species contributed the most to peak standing crop in only half the stands. Stipa pulchra, the only native species among the important species, was more important on serpentine than on sandstone sites. Bromus mollis, the other consistently important species, increased in importance with decreasing moisture supply on both soils. The sandstone grasslands sustained a greater biomass, were more productive, and were less diverse than serpentine grasslands. Within the grasslands as a whole, productivity was inversely related to diversity and positively related to dominance. Stability, however, was related to neither productivity, diversity, or dominance. Thus productivity may increase in such a system with no sacrifice in stability. Properties of sandstone grasslands were clearly related to the habitat gradient from cool, moist sites to warm, dry sites. There was no such relationship in serpentine grasslands. Dominance—diversity curves generally fit previously described models, except on southwestern serpentine exposures. The annual grassland vegetation is a mosaic of floristic composition and ecological properties, shifting in response to habitat patterns but without abrupt discontinuities.

Ten samples of smooth brome ergot, collected in three midwestern states, were examined, described, and analyzed for moisture, fat, and alkaloid content. The moisture and fat concentrations were lower than those which have been reported for rye ergot, but the average alkaloid content of the samples slightly exceeded, and in the case of ergonovine more than doubled the N. F. IX requirement. Paper partition chromatography verified the identity of the water‐soluble alkaloid as ergonovine and established the presence of both ergotamine and ergotoxine in the water‐insoluble alkaloid group. Cultures prepared from these samples showed normal saprophytic growth and were capable of parasitizing rye.

Chromosome numbers and meiotic behavior were determined in clones of Bromus inermis, Bromus pumpellianus, and the Bromus erectus complex. Clones of B. inermis were octoploid (2n = 56) or near-octoploid, one aneuploid having 2n = 54 chromosomes. B. pumpellianus clones were octoploid, with one bearing a B chromosome. B. erectus-type clones had 56, 59, 65, or 70 chromosomes. Meioses varied widely among plants in extent of irregularity. Meiotic behavior was studied in detail and the sequential interrelationships of irregularities at meiotic stages analyzed. Significant or highly significant positive correlations were obtained for the B. pumpellianus clones between percentages of non-stainable pollen and frequencies of metaphase I univalents, anaphase II laggards, and quartet micronuclei. These relationships were non-significant for the B. inermis and B. erectus-type clones. A significant negative correlation was determined between percentage of non-stainable pollen and percentage of seed set following open pollination, but other relationships between meiotic irregularities or pollen stainability and seed-setting characteristics were non-significant. The wide range in chromosome number and meiotic behavior encountered in material commonly distributed on this continent as "B. erectus” may be due to interspecific hybridization in nurseries in which Bromus introductions are grown. Interspecific hybridization may be partially responsible also for aneuploidy and meiotic irregularity in B. inermis.