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The grass genera of the world

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

Pariana Aub.

Including Eremitis Doell, Parianella

Habit, vegetative morphology. Perennial; from a creeping rootstock with crowded stems. The flowering culms leafless, or leafy. Culms about 50–200 cm high; woody and persistent, or herbaceous (Eremitis); to 0.5 cm in diameter; nearly always unbranched above (sparse branching recorded in P. multiflora). Culm nodes glabrous. Culm internodes hollow (Eremitis). Plants unarmed. Leaves not basally aggregated; auriculate; with auricular setae. Sheath margins free. The sheaths with (Pariana sensu stricto) or without (Eremitis) scarlike marks. Leaf blades linear to elliptic; broad; shortly pseudopetiolate; cross veined. Ligule present (often very short); not truncate; up to 5 mm long. Contra-ligule absent.

Reproductive organization. Plants monoecious with all the fertile spikelets unisexual; without hermaphrodite florets. The spikelets of sexually distinct forms on the same plant; female-only and male-only. The male and female-fertile spikelets mixed in the inflorescence (in verticils, each comprising a central female surrounded by (4-)5(-6) males). The spikelets overtly heteromorphic. Plants probably outbreeding (with evidence of entomophily, in Pariana sensu stricto), or inbreeding (Eremitis?); with hidden cleistogenes (Eremitis), or without hidden cleistogenes (Pariana sensu stricto). The hidden cleistogenes in Eremitis subterranean. Not viviparous.

Inflorescence. Inflorescence a false spike, with spikelets on contracted axes (the spikelets in verticils, the whole reduced to a single terminal verticil with vestiges below it in Eremitis); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes disarticulating; disarticulating at the joints (of several segments which separate at maturity (Pariana), or only the terminal segment disarticulating (Eremitis)). Spikelets in verticils of (5-)6(-7); not secund; sessile and pedicellate; consistently in ‘long-and-short’ combinations; in pedicellate/sessile combinations (the female spikelet sessile, the surrounding males on short pedicels). The ‘shorter’ spikelets female-only. The ‘longer’ spikelets male-only.

Female-sterile spikelets. The male spikelets with their short pedicels flattened and coalescent, the florets having (2–)10–40 stamens with their filaments free or joined. The male spikelets with glumes (but some sometimes suppressed); 1 floreted. Male florets (2–)3–40 staminate (Pariana sensu stricto), or 2 staminate (Eremitis). The staminal filaments free, or joined.

Female-fertile spikelets. Spikelets 5–13 mm long; not noticeably compressed; disarticulating above the glumes. Rachilla terminated by a female-fertile floret. Hairy callus absent.

Glumes two; more or less equal; long relative to the adjacent lemmas; hairless; pointed; awnless; similar. Lower glume 1–3 nerved. Upper glume 1–3 nerved. Spikelets with female-fertile florets only.

Female-fertile florets 1. Lemmas decidedly firmer than the glumes; becoming indurated; hairless; non-carinate; without a germination flap; 3 nerved. Palea present; relatively long; entire; awnless, without apical setae; indurated; several nerved; keel-less. Lodicules present; 3; free; fleshy; ciliate, or glabrous; not toothed; heavily vascularized. Stamens 0. Ovary apically glabrous. Styles fused, or free to their bases. Stigmas 1 (and not plumose, in Eremitis), or 2 (plumose, in Pariana).

Fruit, embryo and seedling. Fruit free from both lemma and palea; small to medium sized. Hilum long-linear (at least in Eremitis). Endosperm containing only simple starch grains (Eremitis). Embryo with an epiblast; with a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins overlapping.

First seedling leaf without a lamina (at least in Eremitis).

Abaxial leaf blade epidermis. Papillae present. Intercostal papillae several per cell. Long-cells similar in shape costally and intercostally (fairly short). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type; 66–90 microns long. Microhair apical cells 18–38 microns long. Microhair apical cell/total length ratio 0.26–0.52. Stomata common. Subsidiaries tall dome-shaped, or triangular. Intercostal short-cells common; silicified. Intercostal silica bodies vertically elongated-nodular, or cross-shaped and vertically elongated-nodular. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies oryzoid and ‘panicoid-type’ (occasionally tall-narrow-crenate); commonly cross shaped; not sharp-pointed.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; with arm cells; with fusoids. Leaf blade adaxially flat. Midrib conspicuous; seemingly having a conventional arc of bundles (?-a large central bundle and two laterals, but whether there is a complex is not clear from published descriptions); with the vascular bundles embedded in large-celled, colourless ground tissue. Bulliforms present in discrete, regular adaxial groups; in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’. Sclerenchyma all associated with vascular bundles.

Cytology. Chromosome base number, x = 11, or 12. 2n = 44 and 48.

Classification. Watson & Dallwitz (1994): Bambusoideae; Oryzodae; Olyreae (?). Soreng et al. (2015): Bambusoideae; Bambusodae; Olyreae (including Parianella); Parianinae. 34 species.

Distribution, phytogeography, ecology. Tropical South America.

Shade species. Forest floor plants.

References, etc. Leaf anatomical: Metcalfe 1960.

Special comments. Fruit data wanting. Illustrations. • P. campestris: P. Beauv. (1812). • P. intermedia: Fl. Brasiliensis 2 (1871)

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.’.