| # The grass genera of the world |

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

### Calyptochloa C.E. Hubb.

Type species: Type: C. gracillima C.E.Hubb.

Habit, vegetative morphology. Mat-forming perennial; decumbent. Culms 15–40 cm high; herbaceous; amply to sparswly branched above. Culm nodes glabrous. Culm leaf sheaths rounded. Culm internodes hollow. Young shoots intravaginal. Leaves not basally aggregated; non-auriculate. Leaf blades narrow; 2–8 mm wide; folded; without cross venation; disarticulating from the sheaths; rolled in bud. Ligule a fringe of hairs. Contra-ligule absent.

Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality. Plants exposed-cleistogamous, or chasmogamous; with hidden cleistogenes, or without hidden cleistogenes. The hidden cleistogenes when present, in the leaf sheaths (borne singly, very modified).

Inflorescence. Inflorescence few spikeleted; a single raceme (loose, spike-like); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets solitary; not secund; pedicellate. Pedicel apices truncate, or cupuliform.

Female-fertile spikelets. Spikelets 3.5 mm long; lanceolate, or ovate; adaxial; compressed dorsiventrally; falling with the glumes. Rachilla terminated by a female-fertile floret. Hairy callus absent.

Glumes two; very unequal; (the longer) long relative to the adjacent lemmas; (the upper) hairy (stiffly pilose dorsally and on the margins); awnless; very dissimilar (the lower vestigial, represented by a tiny scale). Lower glume 0 nerved. Upper glume 7 nerved. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 1; epaleate; sterile. The proximal lemmas awnless; 7 nerved; hairy, decidedly exceeding the female-fertile lemmas; less firm than the female-fertile lemmas to similar in texture to the female-fertile lemmas (chartaceous); not becoming indurated.

Female-fertile florets 1. Lemmas similar in texture to the glumes to decidedly firmer than the glumes; striate; becoming indurated (slightly); yellow in fruit, or brown in fruit; entire; pointed; awned (attenuate into the awn). Awns 1; median; apical; non-geniculate; slightly curved; much shorter than the body of the lemma to about as long as the body of the lemma. Lemmas hairless; non-carinate; having the margins lying flat on the palea; 3 nerved. Palea present; relatively long; entire (pointed); awnless, without apical setae; textured like the lemma; 2-nerved. Lodicules present; 2; free; fleshy; glabrous. Stamens 3. Anthers 1.2–2 mm long; not penicillate. Ovary apically glabrous. Styles free to their bases. Stigmas 2.

Fruit, embryo and seedling. Fruit small; compressed dorsiventrally. Hilum short. Embryo large; waisted.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally (narrow-rectangular); of similar wall thickness costally and intercostally (thin walled). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type; 54–69 microns long; 6–9 microns wide at the septum. Microhair total length/width at septum 6.3–10. Microhair apical cells 21–33 microns long. Microhair apical cell/total length ratio 0.39–0.48. Stomata common; 33–36 microns long. Subsidiaries triangular. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs (mainly); silicified. Costal short-cells conspicuously in long rows. Costal silica bodies ‘panicoid-type’.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with radiate chlorenchyma; Isachne-type. Leaf blade adaxially flat. Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups; in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’, or nowhere forming ‘figures’. Sclerenchyma all associated with vascular bundles.

Classification. Watson & Dallwitz (1994): Panicoideae; Panicodae; Paniceae. Soreng et al. (2015): Panicoideae; Panicodae; Paniceae; Neurachninae. 1 species (C. gracillima).

Distribution, phytogeography, ecology. Australia.

Shade species; glycophytic. Forests.

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

Illustrations. • Calyptochloa gracillima: Hook. Ic. Pl. 33 (1935). • Calyptochloa gracillima, spikelet: Stanley & Ross (1989), Flora of SE Queensland.

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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