Stolonochloa E.J.Thomps

Thompson, Edward John, 2022, Stolonochloa, a new Australian genus segregated from Panicum (Poaceae: Panicoideae: Paniceae: Boivinellinae) based on phenetic analysis of morphological data, Phytotaxa 568 (2), pp. 99-148 : 135-137

Stolonochloa E.J.Thomps ., nov. gen.

Type:— Stolonochloa pygmaea (R.Br.) E.J.Thomps.

(= Panicum pygmaeum Brown 1810: 191 )

Stoloniferous perennials with ascending fertile culms. Culm internodes glabrous; with pith. Leaf sheaths pubescent; one margin ciliate. Ligule a fringed membrane. Leaf blades lanceolate, base truncate, pseudopetiolate, proximal margins ciliate. Inflorescence a terminal open panicle; spikelets appressed to branches; branch axils with pulvinii. Pedicels mostly c. 2 mm long; apex bowl-shaped with thin walls, glabrous. Spikelets two-flowered; adaxial, dorsally compressed, elliptical in outline. Lower glume, membranous, glabrous,0–3-veined. Upper glume 5-veined, membranous, aslongas lower lemma. Lower floret neuter. Lemma 5-veined, similar to upper glume. Paleaabsent. Upper floret hermaphrodite; glossy, thin, indurated, pliable, brittle, tightly clasping caryopsis, glabrous. Upper lemmasubequal to lower lemma;5- veined; margins flat, distally hyaline, apex minutely hairy; smooth, without papillae; apex mucronate; germination lid inconspicuous. Upper palea 2-veined; minutely hairy on back at apex.Anthers 3. Caryopsis dorsi-ventrally compressed; hilum punctiform.

Etymology: The genus name is derived from the Greek stelekhos meaning “trunk, stem, log” cognate with the Latin stolon “shoot, sucker” after the horizontal growth habit with runners rooting at the nodes, shared by the two species, and from the Greek chloe for “young green corn or grass”.

KEY TO THE SPECIES OF STOLONOCHLOA

(Adapted from Simon & Alfonso (2022))

1. Inflorescences branches spreading, pilose in axils; leaf sheaths pilose with tuberculate-based hairs 1.6–2.0 mm long; spikelets <2 mm long ........................................................................................................................................................................... S. pygmaea

Inflorescence branches appressed, glabrous in axils or with hairs to 0.6 mm long; leaf sheaths hispid with hairs c. 0.3 mm long; spikelets 1.9–2.4 mm long .......................................................................................................................................... S. lachnophylla