Flowering Culms Research Articles

Fire and grazing interaction in a subhumid grassland: Effects on a dominant tussock grass

AbstractQuestionsHerbivory and fire are the main disturbance drivers in open ecosystems. The aim of this study was to evaluate the effects of fire, cattle grazing, and their interaction on structural traits and the Normalized Difference Vegetation Index (NDVI) of the tussock grass Saccharum angustifolium, and its temporal dynamics in a subhumid grassland.LocationGrasslands of the Eastern Hills, Uruguay.MethodsWe set three blocks (four plots of 300 m2 each) in a homogeneous grazed area dominated by S. angustifolium within a protected area. Each block presented the combinations that emerged from the two levels of cattle grazing (grazed/ungrazed) and burning (burned/unburned) factors. The experimental burning was carried out in the spring. Clump volume, number of flowering culms, NDVI of S. angustifolium, and soil variables were measured for 2 years.ResultsBurning efficiency (plant biomass burned of the total available) was 82%, burn intensity ranged from 178–610 kW m−1, and the soil temperature increased 40% compared with pre‐fire measurements. The volume of S. angustifolium clumps decreased with fire, and the difference between burned–unburned plots decreased with time. The burned–ungrazed treatment increased the number of S. angustifolium flowering culms. NDVI of S. angustifolium clumps increased 50% with fire, and then decreased with time. Soil temperature was higher in burned treatments, and moisture was higher in unburned treatments on some dates. Bulk density, for the 0–5‐cm depth, was 9% higher in burned than in unburned plots irrespective of grazing.ConclusionsOur results provide new data in favor of the management practice carried out by ranchers in Uruguayan grasslands dominated by S. angustifolium. Our data complement the evidence that a fire–grazing interaction can maintain grasslands in different phases of a stable state. Our results constitute a useful contribution for the managers/authorities of the protected area, and can be extrapolated to other tussock grass‐dominated grassland areas.

Influence of flowering on the anatomical structure, chemical components and carbohydrate metabolism of Bambusa tuldoides culms at different ages.

Bamboo forests, which have come to occupy large areas in recent years, naturally undergo the process of blooming. However, bamboo culms and rhizomes degenerate after the plants bloom, resulting in widespread loss of raw materials. Systematic research on the properties and physiology of bamboo culms after flowering is lacking, and whether flowering bamboo culms could be used as raw materials in industry is unclear. In this paper, we compared and measured the fiber morphology, chemical components, and sugar metabolism indexes of non-flowering and flowering Bambusa tuldoides culms at different ages. The results showed that the fibers in the middle internodes of both non-flowering and flowering B. tuldoides culms had the longest length. The fibers completed their elongation within 1 year, but the fiber walls were continually deposited with age. The levels of the chemical components in the nonflowering culms also continually increased with age. The nonstructural carbohydrate (NSC) content and sugar metabolism indexes showed the highest levels in the 2-year culms and then declined in the 3-year culms. Compared to young culms that had not yet flowered, the 3-month-old and 1-year-old flowering culms had a significant decrease in the fiber length and tangential diameter, and their holocellulose and lignin levels also decreased, while the levels of ash, SiO2, 1% NaOH extractives, and benzene-ethanol extractives increased. A correlation analysis showed that sugar catabolism was accelerated in the flowering cluster, which could lead to "starvation death" in bamboo and which had a significant negative impact on the anatomical and chemical properties of the bamboo culms. Generally, the flowering bamboo culms had shorter fibers, higher levels of extractives and ash, and lower holocellulose content, which indicated that bamboo flowering has an adverse effect on the application of such components in the production of pulp, in papermaking, and in other processing and utilization activities. This study revealed the physiological changes in flowering B. tuldoides culms and provided a theoretical basis to inform the utilization of culms in this species.

Bamboo Pleioblastus chino var. hisauchii characteristics before and after flowering

Pleioblastus chino var. hisauchii is an important ornamental bamboo species that rarely flowers. Studies on the change in its material properties before and after flowering were lacking. In this paper, the anatomical, chemical, and mechanical properties of bamboo culms before and after flowering were studied by using the method of bio-wood science. The results showed that after flowering, the morphology and proportion of the fiber, vessel and vascular bundle decreased, and the openings of pits in the vessel wall were enlarged significantly; the contents of the main components such as extractives, lignin, holocellulose, cellulose and pentosan rose, while the ash content dropped. There was a decrease in density and modulus of rupture, and a pronounced fall in modulus of elasticity, while the microfibril angle and crystallinity increased. In general, the strength of bamboo flowering culms decreased and the ability to transport nutrients increased, which were closely related to the changes in internal structure and properties. This meant that bamboo flowering may be monitored or predicted by significant changes in some properties (such as pits and modulus of elasticity) and provide a reference for further research on the mechanism of flowering senescence and delayed flowering in bamboo.

Perennial ryegrass (Lolium perenne) culm and inflorescence density in lawns: Effects of nitrogen fertilization and scalping timing and height

AbstractDuring late spring and early summer, perennial ryegrass (Lolium perenne L.) produces reproductive structures (i.e., culm and inflorescence), that decrease turf quality due to stemminess (i.e., culm remaining) after mowing. Research is required to understand the impact of management practices on visible culm and inflorescence presence. Field experiments were conducted to evaluate perennial ryegrass culm, inflorescence, and turf canopy responses due to various nitrogen (N) fertilization levels, scalping timings and heights. In Experiment 1, N fertilization rates ≥24 kg N ha−1 applied in early May with a slow‐release fertilizer prior to peak flowering (i.e., late May to early June) visibly decreased culms and inflorescences compared with 0 and 12 kg N ha−1. Higher N fertilizer levels, especially 98 kg N ha−1, also resulted in fewer necrotic culms remaining later in the summer along with greater overall turf quality and reduced weed cover. In Experiment 2, scalping perennial ryegrass at 3.8 or 5.1 cm on 25 May, the closest proximity prior to peak flowering, provided the lowest area under the curve (AUC) of green flowering culms. Scalping during or after peak flowering resulted in similar AUC values compared with nonscalped (7.6 cm) turf but did decrease the presence of necrotic culms later in summer to help improve turf quality. Overall, N fertility with a slow‐release fertilizer or a well‐timed scalping influences spring culm and inflorescence density and necrotic culm stemminess in perennial ryegrass turf systems. Additional research on physiological responses, such as carbohydrate partitioning, to these management practices is required.

Sporadic Flowering in <i>Bambusa balcooa</i> Roxb. in Supaul District of Bihar, India

Flowering in bamboos is a very rare phenomenon due to their monocarpic nature and long life cycle. In a survey of bamboo clumps of different districts of North-Eastern Bihar, an unusual sporadic flowering in Haraut bamboo (Bambusa balcooa Roxb.) was recorded at three localities in Supaul district. In India William Roxburgh had observed sporadic flowering in B. balcooa for the first time from Purnea district of Northeastern Bihar. After a very long gap of about 150 years sporadic flowering in B. balcooa is being reported from Supaul district of N-E Bihar. Some of the new findings regarding the morphological characteristics of B. balcooa flowering recorded during the present investigation are (1) that only the flowering culms of the specific clump died without setting seeds and other culms continued to grow normally, (2) young shoots were found to emerge naturally both from unflowered and flowered culms and (3) flowering was observed from basal nodes to upper nodes of the flowering culms and even from the cut flowered culms of one clump. The fear of occurrence of natural calamities due to bamboo flowering had no impact on the people of this region.

Pariana caxiuanensis (Parianinae, Poaceae): a new species of an enigmatic genus of herbaceous bamboos from the Brazilian Amazon

Pariana caxiuanensis (Poaceae) is described and illustrated as a new species from the Brazilian Amazon. The new species is characterized by having the leaves clustered at the apex of the leafy culm, fimbriae few to absent, dimorphic flowering culms, large ligules (2.5–4 mm long), and pubescent to hirsute synflorescences. We present a morphological description, illustrations of the new species, the conservation status assessment, and a key to differentiate P. caxiuanensis from its morphologically related congeners.

Páramo Calamagrostis s.l. (Poaceae): An updated list and key to the species known or likely to occur in páramos of NW South America and southern Central America including two new species, one new variety and five new records for Colombia.

Calamagrostis (syn. Deyeuxia), as traditionally circumscribed, is one of the most speciose genera from páramo grasslands of northwest South America and southern Central America and often dominates these high-elevation habitats. However, it remains difficult for researchers to accurately identify the species due to a lack of floristic treatments for most of the countries containing páramo, with the distribution of many species still very poorly known. In an effort to ameliorate this, we present an updated list and identification keys in English and Spanish (as electronic appendix) to the species of Calamagrostis s.l. known or likely to occur in the páramos of Peru, Ecuador, Colombia, Venezuela, Costa Rica and Panama. Fifty-four species are accepted, constituting 47 species currently circumscribed in Calamagrostis and seven species recently transferred to Deschampsia. Included within this are two new species, Calamagrostiscrispifolius and Deschampsiasantamartensis, which are described and illustrated. Both new species are found in páramos of the Sierra Nevada de Santa Marta (departamento Magdalena), on the northernmost tip of Colombia, with C.crispifolius also found in the Serrania de Perija on the border with Venezuela. Calamagrostiscrispifolius differs from all other species of Calamagrostis s.l. by the presence of strongly curled, readily deciduous leaf blades, amongst numerous other characteristics including open inflorescences with generally patent branches, small spikelets, (3.5–)4–5.5 mm long, with sessile florets and a rachilla prolongation reaching from 2/3 to almost the apex of the lemma, with short hairs (< 1 mm long). Deschampsiasantamartensis is similar to Deschampsiahackelii (=Calamagrostishackelii) from austral South America but differs by its broad, rigid and erect, strongly conduplicate blades, 1.5–2.5 mm wide when folded, ligules of innovations 0.5–1 mm long, truncate or obtuse, ligules of upper flowering culms 3–4 mm long, broadly shouldered with an attenuate central point, ellipsoid spike-like panicle, 3–5.5 long × 1.5–2.5 cm wide, lemma surfaces moderately to lightly scabrous between the veins, lemma apex acute to muticous, entire, rachilla extension often absent and inside of the floret often with hyaline shiny sinuous trichomes to 1 mm long, emerging from the base of the ovary. We also present a broader circumscription of the common species Deschampsiapodophora (=Calamagrostispodophora), with the new variety D.podophoravar.mutica described and illustrated. Deschampsiapodophoravar.mutica principally differs from var. podophora by florets lacking awns and larger habit i.e. multiple taller culms with longer and wider leaf blades forming tussocks, with inflorescences often held within sheaths. Nomenclatural changes are presented, with Deyeuxiamacrostachya newly synonymised under C.macrophylla and C.pittieri, C.pubescens and Deyeuxiapubescens newly synonimised under C.planifolia. Lectotypes are designated for Agrostisantoniana, Calamagrostispisinna, Deyeuxiamacrostachya and Deyeuxiasodiroana. We also document and give notes on five new records of Calamagrostis for Colombia: C.carchiensis, C.guamanensis, C.heterophylla, C.pisinna and C.rigida.

Effect of flowering on physical and mechanical properties of Dendrocalamus brandisii (Munro) Kurz

Dendrocalamus brandisii is one of the giant bamboo species having potential for structural applications. However, very limited data are available on the physical and mechanical properties of this species. This species flowers sporadically as well as gregariously. Gregarious flowering leads to availability of a huge quantity of bamboo. There is considerable apprehension in utilising flowering culms because of the belief that flowered culms are inferior in properties. The study describes the effect of flowering on physical and mechanical properties of D. brandisii. Density, volumetric shrinkage, and bending and compressive strengths of fruited culms were significantly less, whereas the values for non-flowered and flowering culms were comparable. Bending stiffness was comparable for all the three stages of bamboo. Although the bending and compressive strengths of fruited culms of D. brandisii were lower than the non-flowered and flowered culms, still the properties are comparable to the corresponding strength properties reported for other bamboo species. The study reveals that the strength properties of flowering culms of D. brandisii are no way inferior to non-flowered culms and can be used for structural application at par with non-flowered culms.

Flowering in grassland predicted by CO2 and resource effects on species aboveground biomass.

Continuing enrichment of atmospheric CO2 may change plant community composition, in part by altering the availability of other limiting resources including soil water, nutrients, or light. The combined effects of CO2 enrichment and altered resource availability on species flowering remain poorly understood. We quantified flowering culm and ramet production and biomass allocation to flowering culms/ramets for 10years in C4 -dominated grassland communities on contrasting soils along a CO2 concentration gradient spanning pre-industrial to expected mid-21st century levels (250-500μl/L). CO2 enrichment explained up to 77% of the variation in flowering culm count across soils for three of the five species, and was correlated with flowering culm count on at least one soil for four of five species. In contrast, allocation to flowering culms was only weakly correlated with CO2 enrichment for two species. Flowering culm counts were strongly correlated with species aboveground biomass (AGB; R2 =.34-.74), a measure of species abundance. CO2 enrichment also increased soil moisture and decreased light levels within the canopy but did not affect soil inorganic nitrogen availability. Structural equationmodels fit across the soils suggested species-specific controls on flowering in two general forms: (1) CO2 effects on flowering culm count mediated by canopy light level and relative species AGB (species AGB/total AGB) or by soil moisture effects on flowering culm count; (2) effects of canopy light level or soil inorganic nitrogen on flowering and/or relative species AGB, but with no significant CO2 effect. Understanding the heterogeneity in species responses to CO2 enrichment in plant communities across soils in edaphically variable landscapes is critical to predict CO2 effects on flowering and other plant fitness components, and species potential to adapt to future environmental changes.

Histo-anatomical and bio-chemical study of Dendrocalamus brandisii (Munro) Kurz before, during and after flowering

Histo-chemical and bio-chemical changes associated with all the stages of flowering of Dendrocalamus brandisii have been studied. Starch distribution along and across the culm-wall was assessed qualitatively and quantitatively using standard methods. The average starch content varies significantly among the different stages of the culm. The average starch content was lowest in after-flowering culms (3.5%) followed by during flowering culms (7.8%) and maximum in non-flowered bamboo (10.8%). Further it is seen that the starch content also vary long the culm height. High concentration of starch was observed towards the top in before-flowering culms, while the distribution of starch was found to be uniform along the culm height in during-flowering culms. However, in after-flowered culms, comparatively more starch granules were observed in the middle of the culms and very traces were observed both in base and top portion of the culms. Although there was variation in the starch content along the culm heights, these variations were not statistically significant. Histo-chemical and bio-chemical studies on bamboo culms indicate that the starch content of D. brandisii culms depletes after flowering. It was also observed that culms with less starch content (after flowering culms) were more resistant towards powder post beetle attack.

Clonal structure, seed set, and self-pollination rate in mass-flowering bamboo species during off-year flowering events.

Bamboos are typical examples of highly synchronized semelparous species. Their mass-flowering events occur at supra-annual intervals but they sometimes flower on a small scale in off-years. If some bamboo ramets (culms) of a genet flower and die in off-years, whereas other culms of the same genet do not flower synchronously, the genet can still survive blooming in an off-year and could participate in the next mass-flowering event. At genet level, the effect might be similar to that achieved by synchronously reproducing iteroparous plants. In addition, if multiple genets flower simultaneously in off-years, cross-pollination will be promoted. However, it is not known whether all the culms in a genet flower synchronously and whether multiple genets flower in off-years. We determined the clonal structure of three temperate dwarf bamboo species, i.e., Sasa senanensis, S. kurilensis, and S. palmata, at 24 off-year flowering sites and the surrounding areas in northern Japan using seven microsatellite markers. We also estimated seed set at seven of the sites and self-pollination rates at five sites to determine off-year reproductive success. Next, we investigated whether seed sets at the culm level were related to flowering area and/or number of flowering genets, using generalized linear mixed-effect models (GLMMs). Multiple genets flowered at 9/24 flowering sites. We found that 40/96 of the genets identified had some flowering culms. Non-flowering culms were present in 24/40 flowering genets. Seed set was in the range 2.2%–12.5% and the self-pollination rate was 96.3%. In the best GLMM, seed set increased with flowering area. Seeds were produced in off-years, but cross-pollination was rare in off-years. We suggest that some dwarf bamboos may exhibit iteroparity or imperfectly synchronized semelparity at the genet level, a characteristic similar to that of other reproductively synchronous plants. We also found synchronous flowering of a few genets even in off-years.

Dynamic changes of lignin contents of MT-1 elephant grass and its closely related cultivars

Abstract Elephant grass (Pennisetum purpureum Schum.) is a tropical C4 bunchgrass with high rates of growth and biomass production. It has been considered as a new alternative for energy crop in some countries, and expected to provide abundant and sustainable resources of lignocellulosic biomass for the production of solid biofuels. But in addition to cellulose, plant cell walls contain lignin that hinders the degradation of cell wall polysaccharides to simple sugars destined for fermentation to ethanol and biogas. In this paper, five elephant grass cultivars, such as ‘MT-1’ new line (P. purpureum cv. MT-1), ‘Mott’ (P. purpureum cv. Mott), ‘Huanan’ (P. purpureum cv. Huanan), ‘N51’ (P. purpureum cv. N51) and ‘Guimu-1’ ((Pennisetum americanum × P. purpureum) × P. purpureum cv. Guimu No.1) were tested to determine the lignin content using the acetyl bromide method. The lignin contents increased with the growth development for all five cultivars, but the increasing range was different with the difference of cultivar. In particular, the biggest increasing range was between July and August for ‘Huanan’, ‘N51’, ‘Mott’ and ‘MT-1’. At seedling stage, the contents of five cultivars were not significantly different, but the differences were demonstrated at internode elongation stage. At ripening stage, the upper internode of flowering culm had the lowest lignin content, and the basal internode had the highest content for all the five cultivars. The lignin content was very different at different development stage for different cultivars, indicating the differentiations among the five genotypes. As far as the flowering culm (in December) was concerned, the order of lignin content from the highest to the lowest was ‘Huanan’ (22.04% FW) > ‘N51’ (19.65% FW) > ‘Guimu-1’ (17.45% FW) > ‘Mott’ (15.43% FW) ≥ ‘MT-1’ (14.63% FW). In NJ and UPGMA dendrograms, the five cultivars could be divided into two groups, one for ‘MT-1’, ‘Mott’ and ‘Guimu-1’, one for ‘Huanan’ and ‘N51’. This result is consistent with the pedigree relationships among the five cultivars.

Environmental stresses mediate endophyte–grass interactions in a boreal archipelago

Summary 1. Both evolutionary theory and empirical evidence from agricultural research support the view that asexual, vertically transmitted fungal endophytes are typically plant mutualists that develop high infection frequencies within host grass populations. In contrast, endophyte–grass interactions in natural ecosystems are more variable, spanning the range from mutualism to antagonism and comparatively little is known about their range of response to environmental stress. 2. We examined patterns in endophyte prevalence and endophyte–grass interactions across nutrient and grazing (from Greylag and Canada geese) gradients in 15 sites with different soil moisture levels in 13 island populations of the widespread grass Festuca rubra in a boreal archipelago in Sweden. 3. In the field, endophyte prevalence levels were generally low (range = 10–53%) compared with those reported from agricultural systems. Under mesic‐moist conditions endophyte prevalence was constantly low (mean prevalence = 15%) and was not affected by grazing pressure or nutrient availability. In contrast, under conditions of drought, endophyte prevalence increased from 10% to 53% with increasing nutrient availability and increasing grazing pressure. 4. In the field, we measured the production of flowering culms, as a proxy for host fitness, to determine how endophyte‐infected plants differed from uninfected plants. At dry sites, endophyte infection did not affect flowering culm production. In contrast, at mesic‐moist sites production of flowering culms in endophyte‐infected plants increased with the covarying effects of increasing nutrient availability and grazing pressure, indicating that the interaction switched from antagonistic to mutualistic. 5. A concurrent glasshouse experiment showed that in most situations, the host appears to incur some costs for harbouring endophytes. Uninfected grasses generally outperformed infected grasses (antagonistic interaction), while infected grasses outperformed uninfected grasses (mutualistic interaction) only in dry, nutrient‐rich conditions. Nutrient and water addition affected tiller production, leaf number and leaf length differently, suggesting that tillers responded with different strategies. This emphasizes that several response variables are needed to evaluate the interaction. 6. Synthesis. This study found complex patterns in endophyte prevalence that were not always correlated with culm production. These contrasting patterns suggest that the direction and strength of selection on infected plants is highly variable and depends upon a suite of interacting environmental variables that may fluctuate in the intensity of their impact, during the course of the host life cycle.

Clonal Diversity of Arundinaria gigantea (Poaceae; Bambusoideae) in Western North Carolina and its Relationship to Sexual Reproduction: An Assessment Using AFLP Fingerprints

Arundinaria gigantea (river cane), a native bamboo species, was once abundant in river valleys of western North Carolina. Cane stands are now a rare ecosystem due to land use changes, but restoration efforts are underway. River cane reproduces mainly rhizomatously. Sexual reproduction is often characterized by gregarious flowering, followed by death of the flowering culms and possibly of the attached rhizomes. Suggestions have been made in the literature that clusters of flowering culms are monoclonal, but this has not been tested. In this study, leaves were sampled from sterile and fertile culms along transects from two stands in Jackson and Swain counties, North Carolina. Amplified fragment length polymorphism (AFLP) fragments were generated for these samples using three primer pairs. Most of the resulting AFLP fingerprints generated were not identical; however, using a threshold dissimilarity technique, we estimated the probable number of clones in our samples. The majority of fertile culms within a stand were determined to be monoclonal and distinct from some, but not all, of the sterile culms. Cluster analysis confirmed that most of the fertile culms within each stand were more genetically similar to one another than to the sterile culms, and that the two different stands had distinct sets of genotypes, with no genotype overlap between stands. On the basis of these findings, to maximize clonal diversity and minimize the impact of culm loss after flowering, restoration projects should use propagules collected from multiple stands and from multiple localities within a stand.

Anatomía del culmo de Bouteloua y parientes (Gramineae: Chloridoideae: Boutelouinae)

Se analizaron cortes transversales de la región media del tallo de 55 taxa de Boutelouinae, con el fin de explorar la utilidad de sus caracteres en el conocimiento de las relaciones filogenéticas del grupo. A pesar de que los caracteres anatómicos de hoja han mostrado ser útiles para inferir relaciones filogenéticas, el examen microscópico del culmo no revela la existencia de muchos rasgos informativos del aspecto evolutivo. Atributos como las estructuras Kranz, el número y posición de los haces vasculares y los anillos de esclerénquima pueden ser caracteres útiles para inferir relaciones filogenéticas a nivel de familia, tribu o género. La anatomía de tallo sugiere una estrecha relación entre B. eriopoda y B. eriostachya, así como entre B. ramosa y B. breviseta, además apoya la inclusión de los géneros satélites dentro de Bouteloua. Las estructuras Kranz y la forma de los cloroplastos parecen ser los caracteres mas variables de esta región del tallo.

Factors Affecting Reproductive Success in a Rare Grass, Calamagrostis porteri Subsp. Insperata

Factors Affecting Reproductive Success in a Rare Grass, Calamagrostis porteri Subsp. Insperata

Carex radfordii (Section Laxiflorae: Cyperaceae), a New Species from the Southern Appalachians

Carex radfordii Gaddy is a new species of Carex sect. Laxiflorae from the southern Appalachian Mountains of North Carolina, South Carolina, and Georgia. It is a robust species most closely allied to Carex purpurifera Mackenzie and Carex laxiflora Lamarck. Its long awns, glaucous blue-green blades, and brownish white basal sheaths distinguish it from other species of Carex. Carex sect. Laxiflorae has been studied by various investigators in this century. Recently, Bryson (1980) carried out a morphological analysis, and Manhart (1984, 1985, 1986) conducted studies on the morphology, chemotaxonomy, and cytology of the section. Carex laxiflora Lamarck, the namesake for section Laxiflorae, ranges across eastern North America from Maine and southern Quebec south to North Carolina west to Wisconsin and Indiana (Gleason & Cronquist, 1991). It is probably the most variable and complex species in section Laxiflorae and is easily confused with other species in this section. Cariciologists have often wondered whether Carex laxiflora was one species or a complex of species. Mackenzie (1935) described C. purpurifera Mackenzie from specimens that were previously thought to be C. laxiflora, and Bryson's (1985) description of C. manhartii Bryson indicates that C. purpurifera is, in fact, made up of at least two distinct elements. The following species was first seen in the spring of 1979. Since then, I have observed the plant at numerous sites and mapped its distribution. I now conclude that it is a new taxon. Carex radfordii Gaddy, sp. nov. TYPE: U.S.A. South Carolina: Oconee County, in shallow soil, over calcareous rocks, Station Cove, 25 Apr. 1986, L. L. Gaddy s.n. (holotype, CLEMS; isotypes, GA, MO, NCU, NY, US, USCH, WCUH, herbarium of C. T. Bryson). Figure 1. A Carex laxiflora aristis squamis pistillatis longis et laminis venetis glaucis differt; a Carex purpurifera vaginis basalis albidis brunneis differt. Plant caespitose perennial, culms 4-6 dm tall, strongly aphyllopodic, triangular, usually 1.5 x longer than blades. Basal sheaths brownish white, 3-9 cm long, cataphylls well developed, 1-7 cm long. Blades blue-green, glaucous on undersides, 2-5.5 cm long, 7-15 mm wide, midrib well developed, with small teeth dorsally. Staminate spikes 2-4 cm long, 3-6 mm wide, usually solitary, peduncles 4-12 cm long. Pistillate spikes 3-5, peduncles 4-12 cm long, bracts 4-10 cm long, 1-2 mm wide, apices acuminate, sheaths 1-3 cm long, ligules scarious, 4-6 mm long. Perigynia 3-10 per spike, 3-4.5 mm long, obovoid, light green, beak slightly recurved, to 1.5 mm long; scales acute to aristate, often asymmetrical, rarely retuse, serrulate awns 1-5 mm long, usually overtopping the beak of the perigynia, total scale and awn length 3-9 mm, midrib green, margins scarious and hyaline. Achenes obovoid, filling body of the perigynia, 12.5 mm long, 0.8-1.2 mm wide, styles exserted, stigmas 3. I take pleasure in naming this species after Albert E. Radford, Professor Emeritus, University of North Carolina (Chapel Hill), and a lifelong student of Carex. In the mid 1970s, Dr. Radford told me that the Brevard Belt of the Carolinas and Georgia was a rich floristic zone that offered many potential discoveries. I honor him with this discovery. Some of the essential characters of C. radfordii, C. purpurifera, C. laxiflora, C. striatula Michaux, and C. manhartii are compared in Table 1. As may been seen in the table, C. radfordii shares many characters with C. purpurifera and C. laxiflora, and fewer characters with C. striatula and C. manhartii. Furthermore, measurements of the height of the flowering culms, pistillate scale body length, and pistillate scale awn length overlap somewhat in these five species. In height of flowering culm, C. radfordii is a robust species that can only be compared to C. purpurifera. Its blue-green blades (not obvious in herbarium specimens), which are glaucous on the undersides, are similar to those of C. purpurifera, except for the lack of purplish pigment in the basal sheaths. Its pistillate scale awns are usually much longer than those of C. laxiflora, C. NovoN 5: 259-261. 1995. This content downloaded from 157.55.39.255 on Tue, 24 May 2016 05:29:11 UTC All use subject to http://about.jstor.org/terms

Variation and integration in the rare grass Achnatherum (Oryzopsis) hendersonii: phenotypic comparison with parapatric common congeners

Phenotypic properties indicating levels of variation and integration were compared among three populations of a rare bunch grass, Achnatherum (Oryzopsis) hendersonii (tribe Stipeae), and one parapatric population of each of its common relatives Achnatherum (Stipa) lemmonii and Achnatherum (Stipa) thurberiana, sampled from the Colockum Pass area of central Washington, U.S.A. Twenty-five randomly selected plants from each population were measured for both vegetative and spikelet features. The vegetative features were represented by morphometric measurements taken from one leaf on a tiller and the flag leaf on a flowering culm. The spikelet features were based on two to eight spikelets per plant. The three data sets were analyzed separately to compare population level variation both among individuals and among variables (variable covariation). Phenotypic variation among individuals is lowest for A. hendersonii in estimators of both size and shape; within-individual phenotypic variation, as evaluated through among-variable correlation coefficients, is highest for A. hendersonii and lowest for A. thurberiana. The lower level of among-individual variation for A. hendersonii is consistent with biological beliefs about rare species; its higher among-variable variation may indicate less precise control of integration. Key words: rarity, morphological variation and integration, Poaceae, Achnatherum.

SPATIAL VARIABILITY IN SEED PRODUCTION OF THE PERENNIAL BUNCHGRASS BOUTELOUA GRACILIS (GRAMINEAE)

The effects of soil texture and grazing by cattle on the production of seeds of Bouteloua gracilis were evaluated for a semiarid grassland in northeastern Colorado. Ten locations were chosen to represent the range in soil textures and grazing intensities found at the Central Plains Experimental Range research site. Number of flowering culms, inflorescences and seeds, length of each flowering culm, total biomass of reproductive structures (culms, inflorescences, and seeds), and basal area were assessed for 96 B. gracilis plants at each location. Community‐level estimates of density of flowering culms and density of viable seeds were made for each location. Both soil texture and grazing by cattle were important to spatial variability in seed production and other indicators of reproductive effort by B. gracilis. Grazing was important in mediating effects of soil texture. On locations protected from grazing, soil texture had significant effects on seed production; the largest number of seeds was produced on the coarsest‐textured soil and the fewest number on the finest‐textured soil. Relationships between seed production and clay content and between seed production and other indicators of reproductive effort by B. gracilis were different for grazed and ungrazed locations. Spatial variability in seed production of B. gracilis as a result of spatial variability in soil texture and grazing may be important to the continued dominance of this species in the presence of disturbances that vary in time and space.

Ecology of Case-Bearing Moths (Lepidoptera: Coleophoridae) in a New England Salt Marsh

The natural history, oviposition, feeding behavior, and parasitism of Coleophora caespititiella Zeller and C. cratipennella Clemens in a Rhode Island salt marsh are described. C. cratipennella is univoltine and feeds only on the rush Juncus gerardi Loisel. C. caespititiella is bivoltine; the spring generation larvae feed on J. gerardi and the fall generation larvae feed on the annual Salicornia europaea L. This is the first report of bivoltinism in this genus and the first report of a single Coleophora species feeding on plants in these two plant families. In J. gerardi monocultures, oviposition frequency increased with increasing flowering culm density and flower density per culm. In S. europaea monocultures, oviposition frequency initially increased with plant density, but moths appear to be satiated by high-density S. europaea stands. Overall, larvae infested 22% of the J. gerardi seed capsules and reduced seed set in these infested capsules by 60%. C. caespititiella larvae consumed from 4 to 25% of the seeds of S. europaea . Larvae were rarely seen to move from the flowering culm or plant where they were first encountered. Eighteen percent of C. cratipennella larvae and 10% of first-generation C. caespititiella larvae were parasitized by an unidentified ichneumonid wasp. Because these moths feed on two plant species with known asymmetric competitive interactions and consume more seeds of the dominant competitor ( J. gerardi ), the moths may mediate the competitive interactions between J. gerardi and S. europaea .