Digitaria violascens Link (1827: 229)

Verloove, Filip, Gonçalves Silva, Juan J. & Leliaert, Frederik, 2024, Critical notes on grasses (Poaceae) of Madeira, Portugal, Phytotaxa 670 (1), pp. 1-17 : 3

Digitaria violascens Link (1827: 229)

Specimens examined: PORTUGAL. Funchal , Santa Luzia, parque, lawn, 12 September 2021, F. Verloove 14176 ( BR) ; Machico , Portela, track near Caminho do Lameirão, track in open woodland, common, 13 September 2021, F. Verloove 14123 ( BR) .

Digitaria violascens is native to tropical and subtropical Asia and parts of Australia ( Henrard 1950). As a weed, it is naturalized in many other climatologically suitable areas across the world, especially in the Americas. It recently also naturalized in southwestern Europe ( Verloove 2008). In Macaronesia, it is known from Tenerife ( Verloove & Reyes-Betancort 2011). Otto & Verloove (2016) presented a key for the identification of Digitaria in the Canary Islands.

Only two species of Digitaria were known so far from the island of Madeira, D. ciliaris (Retz.) Koeler and D. sanguinalis ( Press & Short 1994, Vieira 2002, Jardim & Sequeira 2008, Menezes de Sequeira et al. 2012). D. violascens is easily distinguished from these two species (and D. radicosa ) based on its very small spikelets (always at most 2 mm long) that are ternate (in groups of 3) on the middle portions of the primary branches (vs. spikelets binate), its upper glumes being subequal in length to the upper lemmas and its upper (fertile) lemmas that are becoming dark brown when mature.

In the island of Madeira, Digitaria violascens was found in relative abundance along a woodland track in Machico, where it seems quite well established. It should be looked for in similar circumstances in that area. In the city of Funchal, it was also recorded as a lawn weed in a park.