Vaseyochloa A. Hitchc.
Named after a botanist, Vasey, plus Greek chloa (grass).
Habit, vegetative morphology. Perennial; rhizomatous and caespitose. Culms 40–100 cm high; herbaceous; unbranched above. Culm nodes glabrous. Plants unarmed. Leaves non-auriculate. Leaf blades narrow; 1–4 mm wide; flat, or rolled (loosely involute); not needle-like; without abaxial multicellular glands; without cross venation; a fringe of hairs. Contra-ligule present (partial, of hairs).
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate; open (5–20 cm long, with few branches); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets 10–18 mm long; narrowly ovate; compressed laterally to not noticeably compressed; disarticulating above the glumes; disarticulating between the florets; with conventional internode spacings. Rachilla prolonged beyond the uppermost female-fertile floret; hairless (glabrous); the rachilla extension with incomplete florets. Hairy callus present (as the stipe-like base of the lemma).
Glumes two; very unequal; shorter than the spikelets; shorter than the adjacent lemmas; hairless; glabrous; pointed (G1), or not pointed (G2); awnless; carinate (G1), or non-carinate (G2); similar (rather firm, G2 broader). Lower glume 3–5 nerved. Upper glume 7–9 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped. Spikelets without proximal incomplete florets.
Female-fertile florets 6–12. Lemmas similar in texture to the glumes (membranous or thinly papery); not becoming indurated; entire; pointed to blunt; awnless; hairy (below); non-carinate (dorsally rounded); without a germination flap; distinctly 7–9 nerved. Palea present; relatively long; probably apically notched (splitting at maturity); awnless, without apical setae; not indurated (membranous); 2-nerved; 2-keeled. Palea keels narrowly winged (and hollowed between the wings). Lodicules present; 2; free; fleshy; glabrous. Stamens 3; with free filaments (these very long). Anthers short; not penicillate; without an apically prolonged connective. Ovary glabrous. Styles free to their bases. Stigmas 2 (sometimes with a vestigial third style).
Fruit, embryo and seedling. Fruit small (2.5–3 mm long); black; ovate-rounded, ventrally deeply concave; compressed dorsiventrally (concavo-convex); sculptured to smooth (obscurely striate). Hilum short. Pericarp fused. Embryo large; with an epiblast; with a scutellar tail; with an elongated mesocotyl internode. Embryonic leaf margins meeting.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present; intercostal. Intercostal papillae over-arching the stomata (at one end); consisting of one oblique swelling per cell (at one end of interstomatals and some intercostal long-cells). Long-cells markedly different in shape costally and intercostally (the costals longer); of similar wall thickness costally and intercostally (medium-thin walled). Mid-intercostal long-cells rectangular; having markedly sinuous walls (and pitted). Microhairs present; elongated; clearly two-celled; chloridoid-type (unusually large). Microhair apical cell wall of similar thickness/rigidity to that of the basal cell. Microhairs (33–)36–39(–42) microns long. Microhair basal cells 24 microns long. Microhairs 10.5–12–14.4 microns wide at the septum. Microhair total length/width at septum 2.7–3.5. Microhair apical cells (7.5–)8.4–9(–12) microns long. Microhair apical cell/total length ratio 0.21–0.27. Stomata common; 21–22.5(–24) microns long. Subsidiaries dome-shaped. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; not paired (solitary); not silicified. Intercostal silica bodies absent. Costal zones with short-cells. Costal short-cells conspicuously in long rows (to solitary - the ‘short-cells’ mainly very long). Costal silica bodies present in alternate cell files of the costal zones; ‘panicoid-type’; mostly dumb-bell shaped (some quite elongated); not sharp-pointed.
Transverse section of leaf blade, physiology. Lamina mid-zone in transverse section open.
C4; XyMS+. PCR sheaths of the primary vascular bundles interrupted; interrupted abaxially only. PCR sheath extensions absent. PCR cell chloroplasts centripetal. Leaf blade with distinct, prominent adaxial ribs to ‘nodular’ in section (the ribs round-topped); with the ribs more or less constant in size. Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups (in all the adaxial furrows); seemingly exclusively in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (with all the bundles); forming ‘figures’ (all bundles). Sclerenchyma all associated with vascular bundles. The lamina margins with fibres.
Cytology. 2n = 60.
Taxonomy. Chloridoideae; main chloridoid assemblage.
Distribution, ecology, phytogeography. 1 species; Texas. Species of open habitats. Sandy, open woods.
Holarctic. Boreal. Atlantic North American. Southern Atlantic North American.
References, etc. Leaf anatomical: this project.
Illustrations. • Abaxial epidermis of leaf blade. • Transverse section of leaf blade
Cite this publication as: Watson, L., and Dallwitz, M. J. (1992 onwards). ‘Grass Genera of the World: Descriptions, Illustrations, Identification, and Information Retrieval; including Synonyms, Morphology, Anatomy, Physiology, Phytochemistry, Cytology, Classification, Pathogens, World and Local Distribution, and References.’ http://biodiversity.uno.edu/delta/. Version: 18th August 1999. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993 onwards, 1998), and Watson and Dallwitz (1994), and Watson, Dallwitz, and Johnston (1986) should also be cited (see References).
