The grass genera of the world
~ Panicum Sect Lorea p.p.
Type species: A. lorea Zuloaga & Morrone.
Habit, vegetative morphology. Perennial; rhizomatous and caespitose, or decumbent (rarely). Leaves mostly basal; auriculate to non-auriculate. Leaf blades linear-lanceolate to lanceolate; not cordate, not sagittate; pungent, flat, or rolled. Ligule present, or absent; when present, a fringed membrane.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality; hermaphrodite.
Inflorescence. Inflorescence lax, paniculate; open.
Female-fertile spikelets. Spikelets elliptic, or ovate; abaxial.
Glumes present; two; very unequal to more or less equal; (the upper) about equalling the spikelets; (the upper) long relative to the adjacent lemmas (subequal to the lower lemma); hairy, or hairless; similar. Lower glume 0.5–0.8 times the length of the upper glume; shorter than the lowest lemma; 1 nerved, or 3 nerved. Upper glume 5(–7) nerved. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 1; paleate. Palea of the proximal incomplete florets fully developed; not becoming conspicuously hardened and enlarged laterally. The proximal incomplete florets male. The proximal lemmas glabrous or pilose, awnless; 5(–7) nerved; more or less equalling the female-fertile lemmas; membranous, less firm than the female-fertile lemmas; not becoming indurated.
Female-fertile florets 1. Lemmas not convolute; decidedly firmer than the glumes; smooth; becoming indurated; not crested; hairy (A. cipoense), or hairless; usually glabrous.
Transverse section of leaf blade, physiology. Supposedly C3; XyMS+.
Special diagnostic feature. Plants not as in Dichanthelium (q.v.).
Cytology. Chromosome base number, x = 10.
Classification. Watson & Dallwitz (1994): not described separately. Soreng et al. (2015): Panicoideae; Arthropogoninae. 15 species.
Distribution, phytogeography, ecology. With a disjunct distribution between the Guiana Highlands and eastern Brazil.
Not known in Australasia.
Species of open habitats. Favouring exposed, rocky soils.
References, etc. Morphological/taxonomic: Sede, S.M., Morrone, O., Giussani, L.M., and Zuloaga, F.O. (2008). Phylogenetic Studies in the Paniceae (Poaceae): a realignment of section Lorea of Panicum. Syst. Bot. 33(2):284–300.
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’.