Thamnocalamus Munro
Including Fargesia Franch., Himalayacalamus Keng f.
Habit, vegetative morphology. Perennial; caespitose. The flowering culms leafy. Culms 100–500 cm high; woody and persistent; to 2 cm in diameter; branched above. Culm nodes glabrous. Primary branches/mid-culm node 5–8. Unicaespitose. Rhizomes pachymorph. Plants unarmed. Young shoots intravaginal. Leaves not basally aggregated; non-auriculate; without auricular setae. Leaf blades broad; pseudopetiolate; cross veined; disarticulating from the sheaths; rolled in bud; a fringed membrane; truncate; 1.5 mm long. Contra-ligule present.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence determinate; without pseudospikelets; a single raceme, or paniculate; contracted; spatheate; a complex of ‘partial inflorescences’ and intervening foliar organs. Spikelets solitary; not secund; pedicellate.
Female-fertile spikelets. Spikelets 15–18 mm long; not noticeably compressed. Rachilla prolonged beyond the uppermost female-fertile floret; hairless; the rachilla extension with incomplete florets. Hairy callus absent.
Glumes two; more or less equal; long relative to the adjacent lemmas; hairless; pointed; awnless (the upper pointed); non-carinate; similar. Lower glume 8–9 nerved. Upper glume 9–13 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped.
Female-fertile florets 2–8. Lemmas similar in texture to the glumes; smooth; not becoming indurated; entire; pointed; awnless, or mucronate (?); hairless; non-carinate; without a germination flap; 10–11 nerved. Palea present; relatively long; apically notched; awnless, without apical setae; not indurated; several nerved; 2-keeled. Lodicules present; 3; free; membranous; ciliate; not toothed; heavily vascularized. Stamens 3. Anthers not penicillate; without an apically prolonged connective. Ovary glabrous; without a conspicuous apical appendage. Styles free to their bases. Stigmas 3.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present; costal and intercostal. Intercostal papillae over-arching the stomata (from the interstomatals); several per cell (small, thickened, one row per cell on the long-cells of astomatal zones, irregular on the interstomatals). Long-cells markedly different in shape costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type. Stomata common. Subsidiaries parallel-sided, or dome-shaped, or parallel-sided and dome-shaped. Guard-cells overlapped by the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs and not paired (solitary and paired). Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies saddle shaped and ‘panicoid-type’; not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; with adaxial palisade; with arm cells; with fusoids. The fusoids external to the PBS. Leaf blade adaxially flat (the ribbing at most slight). Midrib conspicuous; usually with one bundle only (complex in T. aristatus). The lamina symmetrical on either side of the midrib. Bulliforms present in discrete, regular adaxial groups; in simple fans, or associated with colourless mesophyll cells to form deeply-penetrating fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’. Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 12.
Taxonomy. Bambusoideae; Bambusodae; Bambuseae.
Distribution, ecology, phytogeography. 6 species; eastern Asia, South Africa. Helophytic, or mesophytic; glycophytic.
Holarctic and Paleotropical. Boreal. African. Eastern Asian. Sudano-Angolan. South Tropical African.
References, etc. Leaf anatomical: Metcalfe 1960 (‘Arundinaria tessellata’; Soderstrom and Ellis 1982.
Special comments. See Clayton and Renvoize (1986) and Soderstrom and Ellis (1987) for completely different generic interpretations of the species in this circle of affinity: there are no available generic descriptions adequate for the present purpose. Fruit data wanting.
Illustrations. • General morphology
Cite this publication as: Watson, L., and Dallwitz, M. J. (1992 onwards). ‘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.’ http://biodiversity.uno.edu/delta/. Version: 18th August 1999. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993 onwards, 1998), and Watson and Dallwitz (1994), and Watson, Dallwitz, and Johnston (1986) should also be cited (see References).
