| # The grass genera of the world |

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

### Leptosaccharum (Hackel) A. Camus

~ Eriochrysis

Habit, vegetative morphology. Perennial; caespitose. Culms 40–70 cm high; herbaceous; unbranched above. Culm nodes hairy. Leaves mostly basal; non-auriculate. Sheath margins free. Leaf blades narrow; 1.5–2 mm wide; setaceous; without cross venation. Ligule a fringe of hairs; 1–1.5 mm long.

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

Inflorescence. Inflorescence paniculate; contracted (narrow). Inflorescence with axes ending in spikelets. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes ‘racemes’; solitary; persistent (distinctly articulated, but tenacious?). ‘Articles’ densely long-hairy (with conspicuous tufts of golden hairs at each joint and beneath each spikelet). Spikelets not secund; consistently in ‘long-and-short’ combinations (but irregularly so). The ‘shorter’ spikelets hermaphrodite. The ‘longer’ spikelets hermaphrodite.

Female-fertile spikelets. Spikelets unconventional (because they have only one glume, with reduced L2 and P2); 4–7 mm long; compressed dorsiventrally; falling with the glumes. Rachilla terminated by a female-fertile floret. Hairy callus present.

Glumes one per spikelet; long relative to the adjacent lemmas; hairy; not pointed; awnless; non-carinate. 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; 3–5 nerved; decidedly exceeding the female-fertile lemmas; decidedly firmer than the female-fertile lemmas (hairy, similar to the glume); not becoming indurated.

Female-fertile florets 1. Lemmas greatly reduced; less firm than the glumes (flimsy); not becoming indurated; entire; pointed; awnless; hairy; non-carinate; having the margins lying flat on the palea; without a germination flap; 0–1 nerved. Palea present (but reduced, similar to the L2); conspicuous but relatively short; awnless, without apical setae; textured like the lemma (flimsy); not indurated; nerveless; keel-less. Lodicules present; 2; free; fleshy (large); glabrous; not or scarcely vascularized. Stamens 3 (very small, shorter than the lodicules). Anthers not penicillate; without an apically prolonged connective. Ovary apically glabrous. Styles fused to free to their bases. Stigmas 2; red pigmented.

Fruit, embryo and seedling. Fruit small. Pericarp fused. Embryo large.

Abaxial leaf blade epidermis. Costal/intercostal zonation lacking. Papillae absent. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs absent. Stomata absent or very rare; 22.5–27 microns long. Subsidiaries triangular. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs (no zonation, but pairs everywhere). Costal short-cells predominantly paired. Costal silica bodies tall-and-narrow, crescentic, and oryzoid (intergrading); not sharp-pointed.

Transverse section of leaf blade, physiology. C4; XyMS– (but bundles variable). Mesophyll with radiate chlorenchyma. Leaf blade with distinct, prominent adaxial ribs; with the ribs very irregular in sizes. Midrib conspicuous; having a conventional arc of bundles; with colourless mesophyll adaxially. Bulliforms not present in discrete, regular adaxial groups. All the vascular bundles accompanied by sclerenchyma. Sclerenchyma not all bundle-associated. The ‘extra’ sclerenchyma in a continuous abaxial layer.

Classification. Watson & Dallwitz (1994): Panicoideae; Andropogonodae; Andropogoneae; Andropogoninae. Soreng et al. (2015): Panicoideae; Andropogonodae; Andropogoneae. 1 species (L. filiforme).

Distribution, phytogeography, ecology. Brazil & Paraguay.

References, etc. Morphological/taxonomic: Camus 1933. Leaf anatomical: studied by us.

Illustrations. • Leptosaccharum filiforme: Stapf, Icones Plantarum 32 (1927).

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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