Spodiopogon Trin.
From the Greek spodios (ashen) and pogon (beard), perhaps referring to inflorescence hair.
Excluding Eccoilopus
Habit, vegetative morphology. Annual, or perennial. Culms 150 cm high; herbaceous. Culm internodes solid. Leaf blades linear to lanceolate; cordate to sagittate, or not cordate, not sagittate; flat; pseudopetiolate to not pseudopetiolate; without cross venation; ligule present; an unfringed membrane (bearded at its base).
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality (homogamous); overtly heteromorphic (the pedicelled members with imperfect lemma awns, but sometimes with awned glumes).
Inflorescence. Inflorescence paniculate; open (much branched); espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes racemes (usually short); with very slender rachides; disarticulating; disarticulating at the joints. Articles non-linear (clavate, with cupular pubescent apices); not appendaged; disarticulating transversely. Spikelets in triplets, or paired (all paired, or with a terminal triad); sessile and pedicellate; consistently in long-and-short combinations; in pedicellate/sessile combinations. Pedicels of the pedicellate spikelets free of the rachis. The shorter spikelets hermaphrodite. The longer spikelets hermaphrodite.
Female-fertile spikelets. Spikelets compressed dorsiventrally; falling with the glumes (the sessile members falling with adjacent joint and pedicel, the pedicellate members falling from their pedicels). Rachilla terminated by a female-fertile floret. Hairy callus present (bearded). Callus short.
Glumes two; G2 larger; long relative to the adjacent lemmas; hairy, or hairless; awned (sometimes shortly so in pedicellate spikelets), or awnless; very dissimilar (the lower glume chartaceous, pallid, with raised nerves, the upper cymbiform). Lower glume not two-keeled (the nerves equally ribbed); convex on the back; not pitted; relatively smooth; 59 nerved (and ridged). Upper glume 39 nerved. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 1; male, or sterile. The proximal lemmas awnless; 3 nerved; as long as spikelet, similar to G2; similar in texture to the female-fertile lemmas (hyaline); not becoming indurated.
Female-fertile florets 1. Lemmas less firm than the glumes (hyaline); not becoming indurated; incised; 2 lobed; deeply cleft (1/33/4); awned (but those of the pedicellate spikelets imperfectly so). Awns 1; median; from a sinus; geniculate. Lemmas non-carinate; without a germination flap; 3 nerved. Palea present; relatively long; deeply apically notched; awnless, without apical setae (margins ciliate); not indurated (hyaline). Lodicules present; 2; free; ciliate (on the larger lobe); toothed (unequally 2-lobed). Stamens 3. Ovary glabrous. Stigmas 2.
Fruit, embryo and seedling. Fruit fusiform; compressed laterally. Hilum short. Embryo large.
Seedling with a long mesocotyl. First seedling leaf with a well-developed lamina. The lamina broad; curved; about 41 veined.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present; costal and intercostal. Intercostal papillae not over-arching the stomata (for the most part); several per cell (large, irregular, somewhat oblique, mostly in a single row per cell). Long-cells markedly different in shape costally and intercostally (the costals narrower). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; elongated; clearly two-celled; panicoid-type; 2736 microns long; (4.5)4.85.4(6) microns wide at the septum. Microhair total length/width at septum 56.7. Microhair apical cells 1521 microns long. Microhair apical cell/total length ratio 0.50.58. Stomata common; 22.530 microns long. Subsidiaries non-papillate; mostly high to low dome-shaped. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells absent or very rare. Costal short-cells conspicuously in long rows. Costal silica bodies panicoid-type; consistently nodular (elongated); not sharp-pointed.
Transverse section of leaf blade, physiology. C4; XyMS. PCR sheath outlines even. PCR sheath extensions absent. PCR cell chloroplasts seemingly centripetal. Midrib very conspicuous; having a conventional arc of bundles (three large bundles, with small ones between and peripheral to them); with colourless mesophyll adaxially. The lamina symmetrical on either side of the midrib. Bulliforms present in discrete, regular adaxial groups to not present in discrete, regular adaxial groups (epidermis mostly irregularly bulliform); in places in simple fans. Many of the smallest vascular bundles unaccompanied by sclerenchyma. Combined sclerenchyma girders present; forming figures (the primaries and some smaller bundles with conspicuous Is). Sclerenchyma all associated with vascular bundles.
Cytology. 2n = 40 and 42. Chromosomes small.
Taxonomy. Panicoideae; Andropogonodae; Andropogoneae; Andropogoninae.
Distribution, ecology, phytogeography. 10 species; mainly temperate Asia, Middle East. Grassy hillsides.
Holarctic and Paleotropical. Boreal and Tethyan. Indomalesian. Euro-Siberian and Eastern Asian. Irano-Turanian. Indian, Indo-Chinese, and Malesian. Siberian.
Rusts and smuts. Rusts Puccinia. Taxonomically wide-ranging species: Puccinia miyoshiana. Smuts from Ustilaginaceae. Ustilaginaceae Sorosporium, Sphacelotheca, and Ustilago.
References, etc. Leaf anatomical: Metcalfe 1960; this project.
Illustrations. Transverse section 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).