| # The grass genera of the world |

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

### Morronea Zuloaga & Scataglini

~ Dichanthelium, Panicum sensu lato

Type species: M. arundinariae (Trin. ex E Fourn.) Zuloaga & Scataglini.

Habit, vegetative morphology. Perennial. Culms decumbent. Leaf blades not pseudopetiolate. Ligule a fringed membrane.

Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality; hermaphrodite.

Inflorescence. Inflorescence paniculate; lax, spreading, open; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelets not secund.

Female-fertile spikelets. Spikelets elliptic; abaxial; compressed dorsiventrally; falling with the glumes. Rachilla terminated by a female-fertile floret.

Glumes two; very unequal (the lower much reduced or no more than half of the spikelet length, the upper equalling the spikelet); long relative to the adjacent lemmas (i.e., the longer glume). Lower glume (0–)1–3(–5) 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; epaleate; sterile.

Female-fertile florets 1. Lemmas not crested; hairy (pilose all over); 5–7 nerved.

Fruit, embryo and seedling. Hilum short. Embryo large.

Transverse section of leaf blade, physiology. C3.

Classification. Watson & Dallwitz (1994): genus not recognised. Soreng et al. (2015): Panicoideae; Panicodae; Paniceae; Boivinellinae. 6 species.

Distribution, phytogeography, ecology. Mexico to Argentina.

References, etc. Morphological/taxonomic: Scataglini, M.A. and Zuloaga, F.O. (2013). Morronea, a new genus segregated from Panicum (Paniceae, Poaceae) based on morphological and molecular data. Systematic Botany 38(4):1076–1086.

Special comments. Anatomical data wanting.

Illustrations. • Morronea arundinariae (as Panicum), with Panicum aquaticum: Pohl, Flora Costaricensis (1980).

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: 15th June 2025. delta-intkey.com’.

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