Rehia Fijten
Including Bulbulus Swallen
Habit, vegetative morphology. Perennial; caespitose (the slender culms in small dense tufts). The flowering culms leafy. Culms 12–19 cm high; herbaceous; unbranched above; tuberous. Culm nodes hairy. Plants unarmed. Leaves not basally aggregated; without auricular setae. Leaf blades broad; 7–16 mm wide (and 2–4.5 cm long, acute); somewhat cordate, or not cordate, not sagittate (but rounded at the base); pseudopetiolate; cross veined.
Reproductive organization. Plants monoecious with all the fertile spikelets unisexual; without hermaphrodite florets. The spikelets of sexually distinct forms on the same plant; female-only and male-only. The male and female-fertile spikelets mixed in the inflorescence. The spikelets overtly heteromorphic (the males smaller, glabrous).
Inflorescence. Inflorescence indeterminate (with synflorescences); few spikeleted, or many spikeleted; paniculate (panicles terminal, small, borne singly or several together, each of 2–5 spikelet pairs or triplets, scarcely exserted or partially enclosed in a sheath); spatheate; a complex of ‘partial inflorescences’ and intervening foliar organs. Spikelet-bearing axes disarticulating. Spikelets in triplets (sometimes 1 female with 2 male), or paired; pedicellate; consistently in ‘long-and-short’ combinations; unequally pedicellate in each combination. The ‘shorter’ spikelets female-only. The ‘longer’ spikelets male-only.
Female-sterile spikelets. Male spikelets 5 mm long, the floret with 3 stamens. Rachilla of male spikelets terminated by a male floret. The male spikelets without glumes; without proximal incomplete florets; 1 floreted. Male florets 1; 3 staminate.
Female-fertile spikelets. Spikelets 7–8 mm long; lanceolate; with conventional internode spacings. Rachilla terminated by a female-fertile floret. Callus absent.
Glumes two; more or less equal; long relative to the adjacent lemmas; pointed (acute or acuminate, somewhat twisted); awnless; similar (papery). Lower glume 7 nerved. Upper glume 7 nerved. Spikelets with female-fertile florets only.
Female-fertile florets 1. Lemmas decidedly firmer than the glumes (?); becoming indurated; entire; pointed; awnless, or mucronate (?); hairy (pilose); having the margins inrolled against the palea. Palea present. Stamens 0 (but sometimes with staminodes).
Fruit, embryo and seedling. Fruit medium sized (5.5 mm long). Endosperm containing compound starch grains.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous (and the intercostal zones each with a median astomatal zone). Papillae present; intercostal. Intercostal papillae over-arching the stomata (from the adjoining long-cells and interstomatals); several per cell (two or three irregularly shaped papillae, of various sizes, per cell in the stomatal zone). Long-cells markedly different in shape costally and intercostally (the costals narrower); of similar wall thickness costally and intercostally (fairly thin walled). Mid-intercostal long-cells rectangular; having markedly sinuous walls (the sinuosity fairly coarse). Microhairs present; elongated; clearly two-celled; panicoid-type; 63–69 microns long; 5.4–6.9 microns wide at the septum. Microhair total length/width at septum 9.6–12.1. Microhair apical cells 28.5–33 microns long. Microhair apical cell/total length ratio 0.4–0.5. Stomata common (in broad intercostal bands adjacent to the costal zones); 19.5–21 microns long. Subsidiaries papillate (two on each, large and conspicuous); predominantly high dome-shaped, or triangular. Intercostal short-cells common (in the astomatal zones); in cork/silica-cell pairs; silicified. Intercostal silica bodies vertically elongated-nodular. Prickles and macrohairs absent in the material seen. Crown cells absent. Costal short-cells conspicuously in long rows. Costal silica bodies oryzoid (mainly), or ‘panicoid-type’ (a few); sometimes approaching Maltese cross shaped; not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll without arm cells (? - seemingly, in the distorted material seen); with fusoids. The fusoids external to the PBS. Leaf blade adaxially flat. Midrib conspicuous (with a large, round-topped adaxial projection); having a conventional arc of bundles (3 or 5); with colourless mesophyll adaxially. The lamina symmetrical on either side of the midrib. Bulliforms present in discrete, regular adaxial groups (a large, wide group in each intercostal zone); in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’ (all the bundles with an I or an ‘anchor’). Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 10. 2n = 20 (‘Bulbulus nervatus’).
Taxonomy. Bambusoideae; Oryzodae; Olyreae.
Distribution, ecology, phytogeography. 1 species; Brazil. Mesophytic; shade species. In forest.
Neotropical. Amazon.
References, etc. Leaf anatomical: this project.
Special comments. Fruit data wanting.
Illustrations. • Abaxial epidermis of leaf blade
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).
