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The grass genera of the world

L. Watson, T.D. Macfarlane, and M.J. Dallwitz

Lorenzochloa J. & C. Reeder

~ Ortachne

Including Parodiella J. & C. Reeder

Habit, vegetative morphology. Perennial; densely caespitose. Culms 15–38 cm high; herbaceous; unbranched above. Leaves mostly basal; non-auriculate. Leaf blades narrow; acicular (erect, rigid, terete, pungent); not pseudopetiolate; without cross venation; persistent. Ligule an unfringed membrane; not truncate (acute); 2–4 mm long.

Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.

Inflorescence. Inflorescence few spikeleted to many spikeleted; paniculate; open (but narrow and rather few flowered, the branches conspicuously pulvinate); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.

Female-fertile spikelets. Spikelets 2.3–2.6 mm long; compressed laterally, or not noticeably compressed (?); disarticulating above the glumes. Rachilla terminated by a female-fertile floret. Hairy callus present. Callus short.

Glumes two; more or less equal; shorter than the spikelets; shorter than the adjacent lemmas; hairless; not pointed (truncate or emarginate); awnless; non-carinate; similar (firm). Lower glume 3 nerved. Upper glume 3 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.

Female-fertile florets 1. Lemmas tapered into the awn; not convolute; without a crown; similar in texture to the glumes; not becoming indurated; entire; pointed; awned. Awns 1; median; apical; non-geniculate; straight, or flexuous (erect or slightly flexuose, stout with a distinct line of demarcation from the rest of the lemma); hairless (scabrous); about as long as the body of the lemma to much longer than the body of the lemma (to 5 mm long). Lemmas hairy (pubescent on the margins and along the lower half of the mid-nerve); non-carinate; without a germination flap; 5 nerved. Palea present; relatively long; prow-tipped, or not prow-tipped (?); awnless, without apical setae; not indurated (firm); 2-nerved; 2-keeled. Palea back hairy (often pubescent between the keels). Palea keels wingless. Lodicules present; 3 (the posterior smaller). Third lodicule present. Lodicules free; membranous (stipoid); glabrous; not toothed; not or scarcely vascularized. Stamens 3. Anthers not penicillate; without an apically prolonged connective. Ovary apically glabrous. Styles free to their bases. Stigmas 2.

Fruit, embryo and seedling. Fruit small (1.2 to 1.4 mm long); broadly fusiform; compressed dorsiventrally to not noticeably compressed. Hilum long-linear. Embryo small; not waisted; with an epiblast; without a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins meeting.

Abaxial leaf blade epidermis. Costal/intercostal zonation lacking. Papillae absent. Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs absent. Stomata absent or very rare. Prickles abundant in the silica-cell files. Crown cells absent. Costal short-cells conspicuously in long rows (the rows interrupted only by prickles). Costal silica bodies ‘panicoid-type’; dumb-bell shaped (mostly, short), or cross shaped (a few), or nodular (a few, short); not sharp-pointed.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade. Leaf blade with distinct, prominent adaxial ribs; with the ribs very irregular in sizes. Midrib not readily distinguishable; with one bundle only. The lamina symmetrical on either side of the midrib. Bulliforms not present in discrete, regular adaxial groups (Ammophila-type groups of small cells in the furrows). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’ (each main bundle with a large ‘anchor’). Sclerenchyma not all bundle-associated (the feet of the ‘anchors’ joining). The ‘extra’ sclerenchyma in a continuous abaxial layer.

Cytology. Chromosome base number, x = 11. 2n = 22. 2 ploid.

Classification. Watson & Dallwitz (1994): Stipoideae; Stipeae. Soreng et al. (2015): Pooideae; Stipeae. 1 species (L. erectifolia).

Distribution, phytogeography, ecology. High Andes of Venezuela, Colombia, Peru.

References, etc. Leaf anatomical: studied by us.

Illustrations. • L. erectifolia: Pohl (1980), Flora Costaricensis

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: 11th December 2017.’.