The grass genera of the world
Including Panicastrella Moench
Habit, vegetative morphology. Annual; erect or ascending. Culms 1.5–25 cm high; herbaceous. Culm nodes glabrous. Leaves non-auriculate. Sheath margins joined. Leaf blades linear; narrow; 1.5–5 mm wide; flat; without cross venation. Ligule an unfringed membrane (but ciliolate); truncate; 0.5 mm long.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets of sexually distinct forms on the same plant (with sterile, reduced members at the base of the inflorescence), or all alike in sexuality; often hermaphrodite and sterile; overtly heteromorphic (sterile-reduced versus fertile), or homomorphic.
Inflorescence. Inflorescence paniculate; contracted (prickly); capitate, or more or less ovoid (5–15 mm long); espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets associated with bractiform involucres (constituted by the basal, sterile spikelets), or unaccompanied by bractiform involucres, not associated with setiform vestigial branches; not secund; shortly pedicellate, or subsessile.
Female-sterile spikelets. The sterile spikelets, when present, basal and bractlike.
Female-fertile spikelets. Spikelets 4–12 mm long; compressed laterally to not noticeably compressed; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret. Hairy callus present. Callus short.
Glumes two; relatively large (membranous); very unequal to more or less equal; shorter than the spikelets; long relative to the adjacent lemmas; mucronate to awned (the lower with 2–5 veins excurrent as awns, the upper with an excurrent midrib); carinate. Lower glume 2–5 nerved. Upper glume 1 nerved. Spikelets with female-fertile florets only, or with incomplete florets. The incomplete florets distal to the female-fertile florets. Spikelets without proximal incomplete florets.
Female-fertile florets (1–)3–4. Lemmas decidedly firmer than the glumes (leathery); not becoming indurated; awned. Awns 5, or 7; median and lateral (the 5–7 strong lemma veins being produced as flattened awns which become deflexed at maturity, the middle awn the longest); the median similar in form to the laterals; apical; non-geniculate; recurving (deflexing); much longer than the body of the lemma (lemma 2 mm long, the middle awn 4–6 mm long); entered by one vein. The lateral awns shorter than the median. Lemmas hairy; non-carinate; without a germination flap; 5–7 nerved. Palea present; relatively long; awned (two or rarely five veins produced as flattened awns); 2-nerved, or several nerved (up to 5); 2-keeled. Lodicules present, or absent; when present, 2; free; membranous; glabrous; not toothed; not or scarcely vascularized. Stamens 3. Anthers 0.8–1.3 mm long. Ovary apically hairy. Styles fused. Stigmas 2.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small (2 mm long); not noticeably compressed; with hairs confined to a terminal tuft. Hilum short. Embryo small. Endosperm hard; without lipid; containing compound starch grains. Embryo with an epiblast.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular and fusiform; having markedly sinuous walls. Microhairs absent. Stomata common (fairly, but mostly alongside the veins); 36–39 microns long. Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells absent or very rare. Prickle bases abundant. Costal short-cells neither distinctly grouped into long rows nor predominantly paired (mostly solitary). Costal silica bodies horizontally-elongated crenate/sinuous (mostly), or horizontally-elongated smooth.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll without adaxial palisade. Midrib not readily distinguishable; with one bundle only. The lamina symmetrical on either side of the midrib. Bulliforms present in discrete, regular adaxial groups; in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (but the largest bundles with abaxial strands only); forming figures (Is). Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 7 and 9. 2n = 14 and 18. 2 ploid. Chromosomes large.
Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Seslerieae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Sesleriinae. 1 species.
Distribution, phytogeography, ecology. Mediterranean, eastern Asia.
Xerophytic; species of open habitats.
Rusts and smuts. Rusts Puccinia. Taxonomically wide-ranging species: Puccinia hordei.
References, etc. Leaf anatomical: this project.
Illustrations. • E. capitata: P. Beauv. (1812). • E. capitata: Fl. Iraq, 1968
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classifications. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., Macfarlane, T.D., and Dallwitz, M.J. 1992 onwards. The 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. Version: 13th November 2017. delta-intkey.com/grass’.