| # The grass genera of the world |

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

### Colanthelia McClure & Smith

From the Greek kolos (shortened) and anthele (plume or panicle of a reed), referring to an inflorescence characteristic.

~ Aulonemia

Habit, vegetative morphology. Perennial (plants small to very tall, erect or decumbent). The flowering culms leafy. Culms woody and persistent; scandent, or not scandent; branched above. Buds from which the primary culm branches arise 1. Primary branches 4–10; horizontally aligned. The branching dendroid. Culm leaf sheaths present; where recorded, deciduous; leaving a persisten girdle; sometimes not conspicuously auriculate. Culm internodes hollow. Unicaespitose. Rhizomes pachymorph. Plants unarmed. Leaves not basally aggregated; with auricular setae. Leaf blades broad; pseudopetiolate; without cross venation; disarticulating from the sheaths; rolled in bud. Contra-ligule present, or absent.

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

Inflorescence. Inflorescence spatheate; a complex of ‘partial inflorescences’ and intervening foliar organs (with groups of partial inflorescences at the nodes). Spikelet-bearing axes ‘racemes’, or paniculate; clustered; persistent. Spikelets not secund; pedicellate.

Female-fertile spikelets. Spikelets oblong, or lanceolate, or linear; compressed laterally (?); disarticulating above the glumes (?); disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets.

Glumes two, or several (rarely); very unequal; shorter than the adjacent lemmas; awnless; similar. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped. Spikelets without proximal incomplete florets.

Female-fertile florets 3–8 (or more). Lemmas not becoming indurated; awnless, or mucronate (?). Palea present; relatively long; not convolute; entire to apically notched; not indurated; several nerved; 2-keeled (and sulcate). Lodicules present; 3; free; membranous; ciliate; heavily vascularized. Stamens 3. Anthers not penicillate; without an apically prolonged connective. Ovary apically hairy; without a conspicuous apical appendage. Stigmas 2.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present (though seemingly not towards the margins). Intercostal papillae over-arching the stomata; several per cell (irregular, sometimes branched, concentrated and largest around the stomata). Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type; in cingulata 60–78(–84) microns long; 8.4–9 microns wide at the septum. Microhair total length/width at septum 6.7–14. Microhair apical cells 24–31.5(–42) microns long. Microhair apical cell/total length ratio 0.38–0.5. Stomata common; in C. cingulata 25–30 microns long. Subsidiaries low dome-shaped. Guard-cells overlapped by the interstomatals (slightly, even when not covered by papillae). Intercostal short-cells common; not paired (solitary, when not paired with prickle bases); silicified. Intercostal silica bodies tall-and-narrow and saddle shaped. Costal short-cells neither distinctly grouped into long rows nor predominantly paired (mostly solitary). Costal silica bodies saddle shaped (predominantly), or tall-and-narrow.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with adaxial palisade (in places); without arm cells (apparently, in the material seen); with fusoids. The fusoids external to the PBS. Leaf blade adaxially flat. Midrib conspicuous (with a somewhat larger bundle, and a slight abaxial keel: on the other hand, one or two veins near the leaf margins are more strongly keeled); with one bundle only. Bulliforms present in discrete, regular adaxial groups; in simple fans (these large). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; nowhere forming ‘figures’ (the girders mostly narrow). Sclerenchyma not all bundle-associated. The ‘extra’ sclerenchyma in abaxial groups; abaxial-hypodermal, the groups isolated (opposite the bulliform groups).

Classification. Watson & Dallwitz (1994): Bambusoideae; Bambusodae; Bambuseae. Soreng et al. (2015): Bambusoideae; Bambusodae; Bambuseae; Arthrostylidiinae. 7 species.

Distribution, phytogeography, ecology. Brazil.

References, etc. Leaf anatomical: studied by us - C. cingulata (McClure & Smith) McClure.

Special comments. Fruit data wanting.

Illustrations. • Colanthelia cingulata: McClure, New World Bamboos (1973). • Colanthelia distans and Aulonemia effusa (as Arundinaria spp.: Camus (1913). • abbreviations for Camus (1913) figures.

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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