Pogoneura Napper
Habit, vegetative morphology. Annual. Culms 30–60 cm high; herbaceous; unbranched above. Culm nodes glabrous. Plants unarmed. Leaves not basally aggregated. Leaf blades narrow; 2–4 mm wide (about 4 cm long); exhibiting multicellular glands abaxially. The abaxial leaf blade glands on the blade margins. Leaf blades without cross venation; persistent; ligule present; very short, lacerate’ or ‘a line of hairs’, in different descriptions.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence of spicate main branches (of slender racemes from the main rachis); non-digitate. Primary inflorescence branches 12–25 (about 6 cm long, with few spikelets). Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets solitary.
Female-fertile spikelets. Spikelets 5–6 mm long; not noticeably compressed (terete); disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret. Hairy callus present.
Glumes two; very unequal to more or less equal; exceeding the spikelets (enfolding the florets); long relative to the adjacent lemmas; hairless (glabrous, with scabridulous keels); pointed (acute or acuminate); awnless; similar (narrowly lanceolate, membranous). Lower glume much exceeding the lowest lemma; 1 nerved. Upper glume 1 nerved. Spikelets with female-fertile florets only, or with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets 1; merely underdeveloped (vestigial). Spikelets without proximal incomplete florets.
Female-fertile florets 2. Lemmas not becoming indurated; incised; 2 lobed; not deeply cleft (bidentate); shortly awned. Awns 1; median; from a sinus; non-geniculate; hairless; much shorter than the body of the lemma (about 1 mm long). Lemmas hairy (villous on the lateral nerves, the nerves grey-green); non-carinate; 3 nerved. Palea present; relatively long; entire to apically notched (emarginate); awnless, without apical setae; not indurated; 2-nerved; 2-keeled. Palea keels hairy (conspicuously fringed, the hairs grey-green). Lodicules ‘minute or missing’. Stamens 3. Anthers 0.4–0.5 mm long. Ovary glabrous. Stigmas 2.
Fruit, embryo and seedling. Fruit ellipsoid; slightly compressed dorsiventrally.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells markedly different in shape costally and intercostally (the costals narrower and longer); of similar wall thickness costally and intercostally (walls of medium thickness). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; elongated; clearly two-celled; chloridoid-type (the basal cell quite long and expanding distally). Microhair apical cell wall of similar thickness/rigidity to that of the basal cell. Microhairs (27–)28.5–33(–36) microns long. Microhair basal cells 21–24 microns long. Microhairs 6.9–8.4 microns wide at the septum. Microhair total length/width at septum 3.2–4.8. Microhair apical cells 7.5–9 microns long. Microhair apical cell/total length ratio 0.23–0.33. Stomata common; 19.5–24–27 microns long. Subsidiaries all dome-shaped. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs and not paired (some solitary); silicified. Intercostal silica bodies present and perfectly developed; mostly saddle shaped (small). Costal short-cells conspicuously in long rows. Costal silica bodies present in alternate cell files of the costal zones; exclusively saddle shaped; 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. Leaf blade adaxially flat. Midrib conspicuous (via a larger bundle with more abaxial sclerenchyma, and a small sharp keel); with one bundle only. Bulliforms present in discrete, regular adaxial groups; in simple fans (the large median cell deeply penetrating). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (but few: most bundles with a broad abaxial girder and a small adaxial strand); forming ‘figures’ (a few primaries with I’s). Sclerenchyma all associated with vascular bundles. The lamina margins with fibres.
Taxonomy. Chloridoideae; main chloridoid assemblage (cf. Leptochloa).
Distribution, ecology, phytogeography. 1 species; East Africa.
Paleotropical. African. Sudano-Angolan. Sahelo-Sudanian and Somalo-Ethiopian.
References, etc. Morphological/taxonomic: Napper 1963. Leaf anatomical: this project.
Special comments. Fruit data wanting.
Illustrations. • Abaxial epidermis 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).
