| # The grass genera of the world |

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

### Erianthecium L. Parodi

Alluding to hairy florets.

Habit, vegetative morphology. Perennial; caespitose. Culms 30–45 cm high; herbaceous; tuberous. Culm nodes glabrous. Leaves non-auriculate. Leaf blades linear; narrow; 3–5 mm wide; flat; without cross venation. Ligule an unfringed membrane; truncate to not truncate; 3–4 mm long.

Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets; exposed-cleistogamous.

Inflorescence. Inflorescence few spikeleted (8–12); paniculate; contracted; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.

Female-fertile spikelets. Spikelets 7–8 mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with conventional internode spacings. Rachilla prolonged beyond the uppermost female-fertile floret; hairless. Hairy callus absent.

Glumes two; relatively large; very unequal to more or less equal (the upper somewhat longer); shorter than the spikelets; long relative to the adjacent lemmas; hairless; glabrous; pointed (acute); awnless; carinate; similar (lanceolate-acute, papery). Lower glume somewhat shorter than the lowest lemma; 3 nerved, or 5 nerved. Upper glume 7 nerved. Spikelets with female-fertile florets only, or with incomplete florets. The incomplete florets if present, distal to the female-fertile florets. The distal incomplete florets if present, merely underdeveloped.

Female-fertile florets 3–5. Lemmas similar in texture to the glumes (papery or leathery); not becoming indurated; entire (according to the original description), or incised (according to Clayton and Renvoize 1986); if incised, 2 lobed; not deeply cleft (bidentate, according to Clayton and Renvoize); awned. Awns 1; median; dorsal (according to the original description), or from a sinus (or from behind it?); from near the top; non-geniculate; hairless; much shorter than the body of the lemma to about as long as the body of the lemma; entered by one vein. Lemmas densely hairy; non-carinate; without a germination flap; 7 nerved, or 9 nerved. Palea present; relatively long; tightly clasped by the lemma; apically notched; awnless, without apical setae; textured like the lemma; not indurated; 2-nerved; 2-keeled. Palea back hairy. Palea keels wingless; hairy (long-ciliate). Lodicules present; 2; free; membranous; glabrous; not toothed; not or scarcely vascularized. Stamens 3. Anthers about 1.5 mm long; not penicillate; without an apically prolonged connective. Ovary apically glabrous. Styles free to their bases. Stigmas 2 (‘pubescent, terminally exserted’).

Fruit, embryo and seedling. Fruit small (1 mm long); ellipsoid to subglobose; compressed dorsiventrally (dorsally convex, ventrally flat). Hilum short. Embryo small. Endosperm liquid in the mature fruit, or hard; with lipid; containing compound starch grains. Embryo with an epiblast.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells markedly different in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells fusiform; having straight or only gently undulating walls. Microhairs absent. Stomata absent or very rare. Intercostal short-cells absent or very rare. Macrohair bases common. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous, or rounded (a few), or ‘panicoid-type’ (some); when panicoid type, mainly cross shaped and nodular (the latter elongated).

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Leaf blade ‘nodular’ in section to adaxially flat; with the ribs more or less constant in size. Bulliforms present in discrete, regular adaxial groups; in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present. Sclerenchyma all associated with vascular bundles.

Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Poeae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Calothecinae. 1 species (E. bulbosum).

Distribution, phytogeography, ecology. Uruguay.

Species of open habitats. Stony slopes.

References, etc. Morphological/taxonomic: Parodi 1938. Leaf anatomical: studied by us.

Illustrations. • Erianthecium bulbosum: Nicora & Rúgolo de Agrasar (1987).

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: 15th June 2025. delta-intkey.com’.

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