Scutachne A. Hitchc. & Chase
Habit, vegetative morphology. Perennial; caespitose. Culms 40–70 cm high; herbaceous. Culm nodes glabrous. Leaves mostly basal; non-auriculate. Leaf blades narrow; 4–6(–10) mm wide; without cross venation; persistent.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets of sexually distinct forms on the same plant, or all alike in sexuality (the short-pedicelled members poorly-developed or missing); hermaphrodite and sterile.
Inflorescence. Inflorescence a single spike (contracted about the primary branches), or paniculate; open; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate; consistently in ‘long-and-short’ combinations, or not in distinct ‘long-and-short’ combinations; sometimes unequally pedicellate in each combination. The ‘shorter’ spikelets sterile. The ‘longer’ spikelets hermaphrodite.
Female-fertile spikelets. Spikelets 5 mm long; compressed dorsiventrally; falling with the glumes; with a distinctly elongated rachilla internode between the glumes. Rachilla terminated by a female-fertile floret. Hairy callus absent.
Glumes two; relatively large; very unequal; (the upper) about equalling the spikelets (the lower half as long); (the upper) long relative to the adjacent lemmas; (the upper) hairy; pointed; awnless; non-carinate; very dissimilar (the lower small, hyaline and appressed to the rachilla, the upper large and firm). Lower glume 7–9 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; paleate. Palea of the proximal incomplete florets not becoming conspicuously hardened and enlarged laterally. The proximal incomplete florets male. The proximal lemmas awnless; 5 nerved; more or less equalling the female-fertile lemmas; less firm than the female-fertile lemmas (leathery, like the upper glume).
Female-fertile florets 1. Lemmas acuminate to a puberulous point; similar in texture to the glumes to decidedly firmer than the glumes; pointed; awnless; hairless; non-carinate; having the margins lying flat on the palea; with a clear germination flap; 5 nerved. Palea present; relatively long; 2-nerved; 2-keeled. Lodicules present; 2; free; fleshy; glabrous; not or scarcely vascularized. Stamens 3. Anthers not penicillate; without an apically prolonged connective. Ovary glabrous. Styles free to their bases. Stigmas 2; red pigmented.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Mid-intercostal long-cells having markedly sinuous walls. Microhairs present; panicoid-type; 60–66 microns long; 6–8.4 microns wide at the septum. Microhair total length/width at septum 7.1–11. Microhair apical cells 28.5–36 microns long. Microhair apical cell/total length ratio 0.45–0.55. Stomata common; 27–33 microns long. Subsidiaries dome-shaped (mostly), or triangular. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs. Costal short-cells conspicuously in long rows. Costal silica bodies horizontally-elongated smooth and ‘panicoid-type’; mostly cross shaped and nodular; not sharp-pointed.
Transverse section of leaf blade, physiology. C4; XyMS+. PCR sheath outlines uneven. Mesophyll with radiate chlorenchyma. Leaf blade ‘nodular’ in section; with the ribs more or less constant in size. 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 (with the bigger bundles); forming ‘figures’. Sclerenchyma all associated with vascular bundles.
Taxonomy. Panicoideae; Panicodae; Paniceae.
Distribution, ecology, phytogeography. 2 species; Cuba. Species of open habitats. Rocky slopes.
Neotropical. Caribbean.
References, etc. Leaf anatomical: this project.
Special comments. Fruit data wanting.
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).