Pseudechinolaena Stapf
From the Greek pseudein (false, or resembling) and Echinolaena (another grass genus, q.v.).
Including Loxostachys Peter
Excluding Perulifera
Habit, vegetative morphology. Annual; decumbent. Culms 10–60 cm high; herbaceous; branched above. Culm nodes glabrous. Culm internodes solid. Leaves not basally aggregated; non-auriculate. Leaf blades lanceolate (acuminate); broad; 6–15 mm wide; not cordate, not sagittate (but asymmetrical at the base); flat; pseudopetiolate; cross veined; persistent; a fringed membrane; 1.8 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets of sexually distinct forms on the same plant, or all alike in sexuality; hermaphrodite, or hermaphrodite and male-only, or hermaphrodite and sterile (some variously incomplete).
Inflorescence. Inflorescence of spicate main branches (spiciform racemes); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets paired, or solitary (via suppression of one of the pair); secund; pedicellate; consistently in ‘long-and-short’ combinations, or not in distinct ‘long-and-short’ combinations.
Female-fertile spikelets. Spikelets 4.6 mm long; adaxial; compressed laterally; falling with the glumes. Rachilla terminated by a female-fertile floret. Hairy callus absent.
Glumes two; more or less equal (or G1 shorter); long relative to the adjacent lemmas; dorsiventral to the rachis; pointed; awnless; very dissimilar (the lower smooth, the upper gibbous with translucent intercostal glands and often with hooked spines). Lower glume 3 nerved. Upper glume 7 nerved; prickly. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 1; paleate. Palea of the proximal incomplete florets fully developed. The proximal incomplete florets male, or sterile. The proximal lemmas awnless; 3 nerved; decidedly exceeding the female-fertile lemmas (equalling the spikelet); similar in texture to the female-fertile lemmas; not becoming indurated (chartaceous, with thin margins and a delicate hyaline area at the base, laterally compressed).
Female-fertile florets 1. Lemmas lanceolate; similar in texture to the glumes to decidedly firmer than the glumes (papery); smooth; not becoming indurated; entire; pointed; awnless; hairless (sometimes with hooks); non-carinate (convex on the back); having the margins inrolled against the palea; with a clear germination flap; 3–5 nerved. Palea present; entire; awnless, without apical setae; textured like the lemma; not indurated; 2-nerved. Lodicules present; 2; free; fleshy; glabrous. Stamens 3. Anthers not penicillate. Ovary glabrous. Styles fused, or free to their bases. Stigmas 2; red pigmented.
Fruit, embryo and seedling. Fruit small (1.5 mm long); ellipsoid; compressed dorsiventrally (ventrally flattened). Hilum short. Embryo large; waisted. Endosperm hard; without lipid.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells of similar wall thickness costally and intercostally (thin walled). Intercostal zones with typical long-cells (though these rather short and broad). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type; (36–)39–42(–48) microns long; (3.3–)3.9–4.5(–5.4) microns wide at the septum. Microhair total length/width at septum 6.7–11.8. Microhair apical cells 13.5–15–19.5 microns long. Microhair apical cell/total length ratio 0.32–0.42. Stomata common; about 27 microns long. Subsidiaries triangular. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells absent or very rare; not paired (those seen usually solitary); silicified, or not silicified. Costal short-cells conspicuously in long rows. Costal silica bodies ‘panicoid-type’; not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with radiate chlorenchyma; Isachne-type. Leaf blade ‘nodular’ in section; with the ribs more or less constant in size. Midrib conspicuous; with one bundle only; with colourless mesophyll adaxially (associated with the median bundle). Bulliforms present in discrete, regular adaxial groups; in simple fans (these wide, occupying most of the shallow intercostal depressions). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’. Sclerenchyma all associated with vascular bundles.
Cytology. 2n = 36.
Taxonomy. Panicoideae; Panicodae; Paniceae.
Distribution, ecology, phytogeography. 6 species; 5 in Madagascar, 1 pantropical. Mesophytic; shade species; glycophytic. In forest.
Paleotropical, Neotropical, and Cape. African, Madagascan, and Indomalesian. Sudano-Angolan and West African Rainforest. Indian, Malesian, and Papuan. Caribbean, Venezuela and Surinam, Amazon, Central Brazilian, Pampas, and Andean. Sahelo-Sudanian, Somalo-Ethiopian, South Tropical African, and Kalaharian.
References, etc. Leaf anatomical: this project.
Illustrations. • General aspect. • Abaxial epidermis of leaf blade. Pseudechinolaena polystachya.
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).
