Sartidia de Winter
Name and anagram of Aristida (a related grass genus, q.v.).
Habit, vegetative morphology. Perennial; densely caespitose. Culms 80–200 cm high; herbaceous; unbranched above. Culm nodes glabrous. Culm internodes solid. Plants unarmed. Young shoots intravaginal. Leaves not basally aggregated; non-auriculate. Sheath margins free. Leaf blades linear; narrow; 2–4 mm wide; rolled; not pseudopetiolate; without cross venation; persistent; rolled in bud; a fringed membrane, or a fringe of hairs; truncate; 0.3–1 mm long. Contra-ligule present (as a line of hairs, in S. jucunda), or absent.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate (erect, narrow, often interrupted); open; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets solitary; not secund; pedicellate.
Female-fertile spikelets. Spikelets 12–30 mm long; not noticeably compressed; disarticulating above the glumes. Rachilla terminated by a female-fertile floret. Hairy callus present (densely but shortly bearded). Callus pointed to blunt (shallowly bilobed).
Glumes two; more or less equal; long relative to the adjacent lemmas; free; hairless; glabrous; pointed (acute to acuminate); awned, or awnless; non-carinate (rounded on the back); similar (narrow, the nerves evanescent). Lower glume about equalling the lowest lemma; usually 3 nerved. Upper glume 3 nerved, or 5 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 1. Lemmas subcylindrical, with involute margins, scarcely narrowed above; not convolute (involute); decidedly firmer than the glumes; becoming indurated to not becoming indurated (leathery to cartilaginous); not deeply cleft; awned (cf. Aristida). Awns triple or trifid, commonly with a basal column (or at least with the three spreading awns twisted together basally); apical; non-geniculate; hairless (glabrous or scabrid); about as long as the body of the lemma to much longer than the body of the lemma; persistent. Lemmas hairless (glabrous or scabrid); non-carinate; without a germination flap; 3 nerved; with the nerves non-confluent. Palea present; conspicuous but relatively short (small, scale-like); tightly clasped by the lemma; entire (obtuse); awnless, without apical setae (glabrous); thinner than the lemma; not indurated (leathery below); 2-nerved; 2-keeled (grooved). Palea keels wingless; glabrous. Lodicules present (about equalling or exceeding the palea); 2; free; membranous; glabrous; toothed; heavily vascularized. Stamens 3. Anthers 5–6 mm long; not penicillate; without an apically prolonged connective. Ovary glabrous. Styles free to their bases. Stigmas 2 (plumose); white.
Fruit, embryo and seedling. Fruit free from both lemma and palea (but tightly enclosed by the lemma); medium sized (8–10 mm long); fusiform; longitudinally grooved; compressed dorsiventrally. Hilum long-linear. Embryo small (no more than 1/4 grain length). Endosperm containing compound starch grains. Embryo without an epiblast; without a scutellar tail; with an elongated mesocotyl internode. Embryonic leaf margins meeting.
First seedling leaf with a well-developed lamina. The lamina narrow; erect; 5 veined.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type. Stomata common. Subsidiaries dome-shaped, or dome-shaped and triangular. Costal short-cells conspicuously in long rows. Costal silica bodies ‘panicoid-type’; not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Leaf blade with distinct, prominent adaxial ribs; with the ribs very irregular in sizes. Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (with most bundles); forming ‘figures’ (with most bundles). Sclerenchyma not all bundle-associated. The ‘extra’ sclerenchyma in abaxial groups; abaxial-hypodermal, the groups isolated (opposite the bulliforms).
Cytology. Chromosome base number, x = 11. 2n = 22.
Taxonomy. Arundinoideae; Aristideae.
Distribution, ecology, phytogeography. 4 species; South Africa. Mesophytic; glycophytic.
Holarctic and Paleotropical. Boreal. African and Madagascan. Eastern Asian. Sudano-Angolan and Namib-Karoo. South Tropical African.
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).
