Karroochloa Conert & Túrpe
From the Greek chloa (a grass): a grass from the Karroo region of South Africa.
Sometimes referred to Rytidosperma, Danthonia sensu lato
Habit, vegetative morphology. Annual, or perennial; stoloniferous, or caespitose. Culms 4–40 cm high; herbaceous; unbranched above. Culm nodes glabrous. Culm internodes solid. Plants unarmed. Young shoots extravaginal (rarely), or intravaginal. Leaves mostly basal to not basally aggregated; non-auriculate. Hair-tufted at the mouth of the sheath. Leaf blades linear; narrow; to 2 mm wide; flat, or folded, or rolled; without cross venation; persistent; ligule present; a fringe of hairs. Contra-ligule present (as a line of hairs).
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate; contracted (1–6 cm long); more or less ovoid; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets solitary; not secund; pedicellate.
Female-fertile spikelets. Spikelets 4–6(–7) mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with conventional internode spacings. Rachilla prolonged beyond the uppermost female-fertile floret; hairy; the rachilla extension with incomplete florets. Hairy callus present. Callus short, or long; blunt.
Glumes two; more or less equal (subequal); about equalling the spikelets; long relative to the adjacent lemmas; hairless; glabrous; pointed; awnless; carinate; similar (membranous, the margins and apices hyaline). Lower glume much exceeding the lowest lemma; 3–5 nerved. Upper glume 3–5(–7) nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped; awned. Spikelets without proximal incomplete florets.
Female-fertile florets 3–7. Lemmas with fringes or tufts of white hairs, except in K. curva; similar in texture to the glumes (membranous); not becoming indurated; incised; 2 lobed; deeply cleft; awned. Awns 1, or 3; median, or median and lateral (by small extensions from the lobes); the median different in form from the laterals (when laterals present); from a sinus; geniculate; hairless; about as long as the body of the lemma to much longer than the body of the lemma. The lateral awns shorter than the median (and straight). Lemmas hairy. The hairs in tufts, or not in tufts; in transverse rows, or not in transverse rows. Lemmas non-carinate; without a germination flap; 9 nerved; with the nerves non-confluent. Palea present; relatively long (almost equalling the lemma); entire to apically notched; awnless, without apical setae (glabrous or pilose); textured like the lemma; not indurated (membranous, the margins hyaline); 2-nerved; 2-keeled. Palea keels wingless; glabrous, or scabrous. Lodicules present; 2; free; fleshy; ciliate. Stamens 3. Anthers 1.4–2.2 mm long; not penicillate; without an apically prolonged connective. Ovary glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit free from both lemma and palea (but enclosed); small (0.8–1 mm long). Hilum short. Embryo small.
Ovule, embryology. Micropyle not noticeably oblique. Outer integument covering no more than the chalazal half of the ovule; more than two cells thick at the micropylar margin, or two cells thick at the micropylar margin. Inner integument not thickened around the micropyle. Synergids haustorial (strongly developed); exhibiting large, globular starch grains.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Mid-intercostal long-cells rectangular, or rectangular and fusiform; having markedly sinuous walls. Microhairs present; panicoid-type. Stomata common, or absent or very rare. Subsidiaries dome-shaped. Intercostal short-cells common; in cork/silica-cell pairs, or not paired; silicified. Costal short-cells usually conspicuously in long rows, or neither distinctly grouped into long rows nor predominantly paired (in K. purpurea). Costal silica bodies tall-and-narrow to crescentic (K. purpurea), or ‘panicoid-type’ (usually); usually cross shaped, or dumb-bell shaped.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; Isachne-type (or at least tending to this), or not Isachne-type. Leaf blade with distinct, prominent adaxial ribs to ‘nodular’ in section, or adaxially flat; when ribbed with the ribs more or less constant in size. Midrib not readily distinguishable (apart from position); with one bundle only. Bulliforms present in discrete, regular adaxial groups, or not present in discrete, regular adaxial groups; sometimes in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders absent. Sclerenchyma all associated with vascular bundles.
Special diagnostic feature. Female-fertile lemmas with a bent awn, the awn twisted below. Spikelets 4–6(–7) mm long, inflorescence 10–60 mm long.
Cytology. Chromosome base number, x = 6. 2n = 12 and 24. 2 and 4 ploid.
Taxonomy. Arundinoideae; Danthonieae.
Distribution, ecology, phytogeography. 4 species; southern Africa. Mesophytic; species of open habitats; glycophytic. Grassland and among rocks.
Paleotropical and Cape. African. Namib-Karoo.
References, etc. Morphological/taxonomic: Conert 1969. Leaf anatomical: Conert and Türpe 1969; photos of K. purpurea provided by R.P. Ellis.
Illustrations. • General aspect
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).
