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The grass genera of the world

L. Watson, T.D. Macfarlane, and M.J. Dallwitz

Perulifera A. Camus

~ Pseudechinolaena

Habit, vegetative morphology. Annual. Culms 10–15 cm high; herbaceous; branched above. Culm nodes exposed; hairy. Plants unarmed. Leaves not basally aggregated; non-auriculate; without auricular setae. Sheaths slightly inflated, not keeled. Leaf blades lanceolate; broad; 3–5 mm wide (1.5–4 cm long); rounded at base; flat; more or less pseudopetiolate; without cross venation. Ligule an unfringed membrane (ciliolate); truncate. 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 (but the sterile spikelets so ‘reduced’ as to be confused with the glumes).

Inflorescence. Inflorescence of spicate main branches (a 3.5–6 cm raceme of spike-like racemes). Primary inflorescence branches 4–7. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets solitary (apparently), or paired (‘really’); secund; biseriate; shortly pedicellate, or sessile to subsessile (the sterile member); imbricate; consistently in ‘long-and-short’ combinations (but not obviously so until the sterile spikelet is identified as such). The ‘shorter’ spikelets sterile (reduced to a lanceolate, glabrous glume contiguous with the fertile spikelet). The ‘longer’ spikelets hermaphrodite.

Female-sterile spikelets. The sterile spikelet of each pair reduced to an elongate glume.

Female-fertile spikelets. Spikelets unconventional (because of the reduced sterile spikelet continguous with the G1); 2–2.2 mm long; purple; abaxial; strongly compressed laterally; falling with the glumes. Rachilla terminated by a female-fertile floret.

Glumes two; relatively large; (the upper) long relative to the adjacent lemmas; dorsiventral to the rachis; awned (the G1 attenuate into a 2.5–4 mm awn); very dissimilar (both membranous, the G1 smaller, narrower, attenuate-aristate and asperulous, the G2 basally gibbous, verrucose and mucronate). Lower glume 3 nerved. Upper glume distinctly saccate (swelled out ‘like a wallet’); 7 nerved; probably becoming more or less prickly, or not 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 (with three stamens). The proximal lemmas carinate, subgibbous above; awnless (but rostrate); 3 nerved; decidedly exceeding the female-fertile lemmas; less firm than the female-fertile lemmas (membranous); not becoming indurated.

Female-fertile florets 1. Lemmas laterally compressed, acute; very thinly cartilaginous; smooth; not becoming indurated; entire; pointed; awnless; hairless (shiny); non-carinate (convex); having the margins lying flat on the palea; 3 nerved, or 5 nerved. Palea present; relatively long; somewhat thinner than the lemma (hyaline, less rigid); not indurated; 2-nerved; slightly 2-keeled. Lodicules present; 2; fleshy (lobed); glabrous. Stamens 3 (the anthers deeply sagittate basally and divaricate above, the thecae easily separating to simulate six stamens). Anthers about 1 mm long (relatively long, yellow, the filaments short and thick); not penicillate; without an apically prolonged connective. Ovary apically glabrous. Stigmas 2; red pigmented.

Fruit, embryo and seedling. Fruit free from both lemma and palea; small (0.9 mm long); elongated pyriform; not grooved; compressed laterally, or not noticeably compressed; glabrous. Hilum short. Embryo large; waisted. Endosperm hard.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells markedly different in shape costally and intercostally (the costals much smaller and narrower). Intercostal zones with typical long-cells to exhibiting many atypical long-cells (many of them rather short, some very short). Mid-intercostal long-cells more or less isodiametric or somewhat irregular to rectangular; having markedly sinuous walls (coarsely sinuous). Microhairs present; elongated; clearly two-celled; panicoid-type. Stomata common (but confined to rows alongside the costae). Subsidiaries non-papillate; low to high dome-shaped. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells absent or very rare. With numerous long, slender, cushion-based macrohairs and a few small prickles intercostally. Costal short-cells mostly conspicuously in long rows. Costal silica bodies present and well developed; ‘panicoid-type’; dumb-bell shaped and nodular.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll not Isachne-type; without arm cells; without fusoids. Midrib conspicuous; with one bundle only.

Classification. Watson & Dallwitz (1994): Panicoideae; Panicodae; Paniceae. Soreng et al. (2015): Panicoideae; Panicodae; Paniceae; Boivinellinae (?). 1 species.

Distribution, phytogeography, ecology. Madagascar.

References, etc. Morphological/taxonomic: Camus 1927b.

Special comments. Fruit data wanting.


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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’.

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