| # The grass genera of the world |

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

### Cinna L.

Cinna: an old Greek name for a grass.

Including Abola Adans., Blyttia Fries

Habit, vegetative morphology. Perennial (tall, of wet habitats); rhizomatous, or caespitose (laxly, or the culms solitary). Culms (20–)50–200(–220) cm high; herbaceous; tuberous (somewhat, in C. arundinacea), or not tuberous. Culm nodes glabrous (or somewhat scaberulous). Culm internodes hollow. Leaves non-auriculate. Sheath margins free. Sheaths glabrous. Leaf blades linear; broad to narrow; 1–20 mm wide (to 40 cm long); flat (with scabrous margins); not pseudopetiolate; without cross venation. Ligule an unfringed membrane; 2–10(–12) mm long.

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

Inflorescence. Inflorescence paniculate (with numerous spikelets); open; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.

Female-fertile spikelets. Spikelets (1.9–)2–6(–7.5) mm long; compressed laterally; falling with the glumes. Rachilla prolonged beyond the uppermost female-fertile floret (usually, as a stub or bristle), or terminated by a female-fertile floret (rarely); the rachilla extension with incomplete florets (usually), or naked. Hairy callus absent. Callus short.

Glumes two; more or less equal (the lower sometimes somewhat shorter); long relative to the adjacent lemmas (a little shorter to a little longer); free; hairless; glabrous to scabrous (smooth to scaberulous); pointed (acute or acuminate); awnless (sometimes mucronate); carinate; similar (thinly membranous, the margins hyaline). Lower glume 1 nerved. Upper glume 1 nerved, or 3 nerved. Spikelets with female-fertile florets only (usually), or with incomplete florets (very rarely). The incomplete florets when present, distal to the female-fertile florets. The distal incomplete florets 1; merely underdeveloped. Spikelets without proximal incomplete florets.

Female-fertile florets 1 (nearly always, though the second floret when present is said to be occasionally ‘fertile’). Lemmas similar to the glumes; similar in texture to the glumes to decidedly firmer than the glumes (firmly membranous); not becoming indurated; entire, or incised; when entire pointed, or blunt; awnless, or mucronate, or awned. Awns when present, 1; dorsal; from near the top (or subterminal); non-geniculate; straight; much shorter than the body of the lemma; entered by one vein. Lemmas hairless; carinate; without a germination flap; 3 nerved, or 5 nerved. Palea present; relatively long; thinner than the lemma (hyaline); 1-nerved, or 2-nerved (one veined in C. arundinacea, ostensibly so in the others by apposition of the two veins); one-keeled (literally so in C. arundinacea, ostensibly so by close apposition in the rest). Lodicules present; 2; free; membranous; ciliate; toothed, or not toothed (rarely); not or scarcely vascularized. Stamens 1, or 2. Anthers (0.4–)0.6–1.2(–2.6) mm long. Ovary apically glabrous. Styles free to their bases. Stigmas 2; white.

Fruit, embryo and seedling. Fruit free from both lemma and palea; small (about 2.5 mm long); yellowish brown; compressed laterally. Hilum short. Embryo small. Endosperm liquid in the mature fruit, or hard; with lipid; containing compound starch grains. Embryo with an epiblast; without a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins meeting.

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 common; (30–)33–36(–38) microns long. Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells absent or very rare. Prickles abundant. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous, or horizontally-elongated smooth.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma.

Cytology. Chromosome base number, x = 7. 2n = 28. 4 ploid. Chromosomes ‘large’.

Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Aveneae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Poinae. 3–4 species.

Distribution, phytogeography, ecology. Temperate Eurasia, North & South America.

Helophytic, or mesophytic; shade species; glycophytic.

Rusts and smuts. Rusts — Puccinia. Taxonomically wide-ranging species: Puccinia graminis, Puccinia coronata, and Puccinia recondita.

References, etc. Morphological/taxonomic: Brandenburg, Blackwell and Thieret 1991. Leaf anatomical: studied by us - C. latifolia (Trev.) Griseb.

Illustrations. • Cinna arundinacea: P. Beauv. (1812). • Cinna arundinacea: Hitchcock and Chase (1950).

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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