The grass genera of the world
~ Still referred to Anadelphia (but very distinct)
Habit, vegetative morphology. Annual. Culms 10–50 cm high; herbaceous; branched above to unbranched above. Culm nodes exposed; glabrous. Culm leaves present. Leaves not basally aggregated; ostensibly auriculate from the sheath, when the ligule is split. Leaf blades linear; narrow; about 0.5 mm wide; acicular (triquetrous); without cross venation; persistent. Ligule present (of somewhat peculiar constitution, associated with the narrowness of the blade relative to the sheath); an unfringed membrane (leathery below and on the sides, mimicking auricles); not truncate; 2–3 mm long. Contra-ligule absent.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets of sexually distinct forms on the same plant; hermaphrodite and sterile; overtly heteromorphic; all in heterogamous combinations. Plants presumably inbreeding; exposed-cleistogamous (seemingly).
Inflorescence. Inflorescence paniculate; open; spatheate (and spatheolate); a complex of partial inflorescences and intervening foliar organs. Spikelet-bearing axes very much reduced (each raceme reduced to one triplet, clasped basally by the peculiar, trumpet-shaped tip of the peduncle); the spikelet-bearing axes with only one spikelet-bearing article; solitary; disarticulating; disarticulating at the joints (i.e. at the single articulation). Articles without a basal callus-knob; disarticulating obliquely. Spikelets in triplets; sessile and pedicellate; consistently in long-and-short combinations; in pedicellate/sessile combinations. Pedicels of the pedicellate spikelets free of the rachis. The shorter spikelets hermaphrodite. The longer spikelets sterile.
Female-sterile spikelets. Sterile spikelets 2–4 mm long, reduced to the glumes.
Female-fertile spikelets. Spikelets 6–7 mm long; somewhat compressed dorsiventrally; falling with the glumes (and with the associated pedicellate spikelets). Rachilla terminated by a female-fertile floret. Hairy callus present. Callus long; pointed.
Glumes two; more or less equal; exceeding the spikelets; long relative to the adjacent lemmas; hairless; glabrous; awned; non-carinate; very dissimilar (the lower bidentate, awnless, canaliculate above, the upper round-backed to keeled, with a long, slender terminal awn). Lower glume two-keeled above, the keels closely apposed to form a groove; convex on the back and sulcate on the back; not pitted; relatively smooth; 6 nerved (with no median). Upper glume 3 nerved. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. The proximal incomplete florets 1; epaleate; sterile. The proximal lemmas awnless; 2 nerved (palea-like); more or less equalling the female-fertile lemmas (about 3 mm long); less firm than the female-fertile lemmas to similar in texture to the female-fertile lemmas (hyaline); not becoming indurated.
Female-fertile florets 1. Lemmas stipitate below, with hyaline margins and lobes; less firm than the glumes; not becoming indurated; incised; 2 lobed; deeply cleft; awned. Awns 1; median; from a sinus; geniculate; hairless (scabridulous); much longer than the body of the lemma (to 50 mm long). Awn bases twisted; not flattened. Lemmas hairless; glabrous; non-carinate; without a germination flap; 3 nerved; with the nerves non-confluent. Palea present; conspicuous but relatively short (about 1.5 mm long); awnless, without apical setae; thinner than the lemma to textured like the lemma (hyaline); not indurated; 2-nerved, or nerveless. Palea back glabrous. Lodicules present; 2; fleshy; glabrous. Ovary apically glabrous.
Fruit, embryo and seedling. Fruit small to medium sized (3–4 mm long); ellipsoid; compressed dorsiventrally (slightly, above), or not noticeably compressed; glabrous. Hilum short. Embryo large. Endosperm hard.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells markedly different in shape costally and intercostally (the costals much narrower); of similar wall thickness costally and intercostally (fairly thick walled). Mid-intercostal long-cells rectangular; having markedly sinuous walls (with conspicuous pits). Microhairs present; elongated; clearly two-celled; panicoid-type; 33–42 microns long; 4.5–5.4 microns wide at the septum. Microhair total length/width at septum 6.1–9.3. Microhair apical cells 15–21 microns long. Microhair apical cell/total length ratio 0.45–0.5. Stomata common; 24–27 microns long. Subsidiaries dome-shaped and triangular. Guard-cells overlapping to flush with the interstomatals (more or less flush). Intercostal short-cells absent or very rare (absent, except for a few pairs at costal/intercostal interfaces). Costal short-cells conspicuously in long rows (mostly), or predominantly paired (in some files, and exclusively over the midrib). Costal silica bodies present and well developed; panicoid-type; consistently dumb-bell shaped.
Transverse section of leaf blade, physiology. Leaf blades entirely consisting of midrib.
C4; XyMS. PCR sheath outlines uneven. PCR sheath extensions absent. Midrib having a conventional arc of bundles (the reduced blade with a large median bundle, two mid-lateral primaries and numerous minor bundles); with colourless mesophyll adaxially (the colourless tissue occupying the whole middle of the acicular blade). Bulliforms not present in discrete, regular adaxial groups. All the vascular bundles accompanied by sclerenchyma (in the absence of a conventional lamina). Combined sclerenchyma girders absent (the large bundles with abaxial girders, the small ones with only strands). Sclerenchyma all associated with vascular bundles.
Special diagnostic feature. Spikelets in much-reduced andropogonoid racemes, each of the latter reduced to a single triplet and enclosed at its base by a trumpet-like development of the peduncle tip.
Classification. Watson & Dallwitz (1994): Panicoideae; Andropogonodae; Andropogoneae; Andropogoninae. Soreng et al. (2015): Panicoideae; Andropogonodae; Andropogoneae; Anthistiriinae. 1 species.
Distribution, phytogeography, ecology. Zambia.
Mesophytic; species of open habitats; glycophytic.
References, etc. Leaf anatomical: this project.
Special comments. Anomalous in Anadelphia; cf. Clausospicula. Illustrations. • A. scyphofera, abaxial epidermis of leaf ‘blade’: this project. • A. scyphofera, transverse section of leaf ‘blade’: this project
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classifications. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., Macfarlane, T.D., and Dallwitz, M.J. 1992 onwards. The 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. Version: 13th November 2017. delta-intkey.com/grass’.