A peculiar amphitropical genus of Paniceae (Poaceae, Panicoideae).

A. SCATAGLINI; LIZARAZU, M.; F.O. ZULOAGA

SYSTEMATIC BOTANY

AMER SOC PLANT TAXONOMISTS

Lugar: Laramie; Año: 2014 vol. 39 p. 1108 - 1119

0363-6445

The genus Louisiella (Poaceae, Paniceae) is reviewed. This African monotypic genus was originally circumscribed on the basis of morphological characters. Recent phylogenetic studies have shown its affinity with an American species of Panicum, P. elephantipes. Molecular, morphological, and anatomical characters of Louisiella fluitans and P. elephantipes were nalyzed. Both species share vegetative and reproductive characters, including habit, ligules, blades, inflorescence, and spikelet features, such as a reduced lower glume, a lanceolate upper glume and lower lemma both longer than the upper anthecium, lower palea reduced or absent and lower flower absent, upper anthecium indurate, and a caryopsis with a linear hilum; anatomically, both taxa are Kranz of the PS-subtype, with specialized chloroplasts on the outer parenchymatous sheath. The molecular phylogenetic analysis also corroborates the relationship between these species, with 100% of branch support. As a result, we conclude that P. elephantipes has to be transferred to the herein amphitropical genus Louisiella. Affinities of Louisiella with other genera of Paniceae are also discussed. Finally, two lectotypes are designated for Panicum fistulosum and Digitaria megapotamica.