Hubbardochloa Auquier
Named for C.E. Hubbard, distinguished agrostologist, with Greek chloa (a grass).
Sometimes referred to Muhlenbergia?
Habit, vegetative morphology. Slender annual. Culms 4–12(–17) cm high; herbaceous; branched above. Leaves not basally aggregated; non-auriculate. Leaf blades linear-lanceolate; narrow; 2–5 mm wide; flat, or rolled (convolute when dry); without abaxial multicellular glands; pseudopetiolate (the base very abruptly contracted); without cross venation; a fringe of hairs.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality. Plants seemingly inbreeding; exposed-cleistogamous, or chasmogamous (?).
Inflorescence. Inflorescence paniculate; open; with capillary branchlets; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets solitary; secund, or not secund.
Female-fertile spikelets. Spikelets 1.2–1.4 mm long; fusiform; somewhat compressed laterally; disarticulating above the glumes. Rachilla terminated by a female-fertile floret. Hairy callus present (minute). Callus short; blunt.
Glumes two; more or less equal; exceeding the spikelets; long relative to the adjacent lemmas; hairless; glabrous to scabrous; pointed (the upper being acute), or not pointed (the lower being obtuse-erose); awnless; carinate (the upper), or non-carinate (the lower); slightly dissimilar. Lower glume 1 nerved. Upper glume 1 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 1. Lemmas less firm than the glumes (hyaline-membranous); not becoming indurated; entire; blunt (truncate); awned. Awns 1; median; apical; non-geniculate; flexuous; hairless (scaberulous); much longer than the body of the lemma; entered by one vein. Lemmas hairy (on the margins); non-carinate (dorsally rounded); 1 nerved. Palea absent. Lodicules absent. Stamens 3. Anthers 0.3–0.4 mm long. Ovary glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit small (0.9–1 mm long); fusiform; not noticeably compressed (almost cylindrical). Hilum short. Pericarp fused. Embryo small.
Abaxial leaf blade epidermis. Costal/intercostal zonation fairly conspicuous. Papillae present; very abundant, costal and intercostal. Intercostal papillae several per cell (nearly every cell with one or two rows of smallish, round or branch-paired papillae). Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally (rather thin walled). Mid-intercostal long-cells rectangular; having markedly sinuous walls (the sinuosity coarse). Microhairs present; elongated; clearly two-celled; chloridoid-type. Microhair apical cell wall of similar thickness/rigidity to that of the basal cell. Microhair basal cells 12 microns long. Microhair total length/width at septum 3. Microhair apical cell/total length ratio 0.33. Stomata absent or very rare. Intercostal short-cells absent or very rare; not paired. Intercostal silica bodies absent. No macrohairs or prickles seen. Costal short-cells conspicuously in long rows. Costal silica bodies present and well developed; present in alternate cell files of the costal zones; ‘panicoid-type’; cross shaped, butterfly shaped, and dumb-bell shaped (mostly dumb-bells).
Transverse section of leaf blade, physiology. Lamina mid-zone in transverse section open.
C4; XyMS+. PCR sheath outlines even. PCR sheaths of the primary vascular bundles interrupted; interrupted abaxially only. PCR sheath extensions absent. Mesophyll with radiate chlorenchyma; not traversed by colourless columns. Leaf blade with distinct, prominent adaxial ribs; with the ribs more or less constant in size (round topped, one per bundle). Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups (in every furrow); in simple fans (deeply penetrating). All the vascular bundles accompanied by sclerenchyma. Sclerenchyma all associated with vascular bundles (scanty). The lamina margins with fibres.
Taxonomy. Chloridoideae; main chloridoid assemblage.
Distribution, ecology, phytogeography. 1 species; Rwanda, Burundi, Zambia. Species of open habitats. Stony slopes, in savanna.
Paleotropical. African. West African Rainforest. South Tropical African.
References, etc. Morphological/taxonomic: Auquier 1980. Leaf anatomical: this project.
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).