Axonopus fissifolius (Raddi) Kuhlm. (1922: 87)

Verloove, Filip, Gonçalves Silva, Juan J. & Leliaert, Frederik, 2024, Critical notes on grasses (Poaceae) of Madeira, Portugal, Phytotaxa 670 (1), pp. 1-17 : 2

Axonopus fissifolius (Raddi) Kuhlm. (1922: 87)

Specimen examined: PORTUGAL. Quinta do Palheiro Ferreiro, Jardim “Sunken”, lawns, between cobble stones, a common turf weed, 29 April 2022, F. Verloove 14315 (BR, MADM).

This species is native to the New World but increasingly found as a weed in subtropical and warm-temperate regions of the Old World. In Europe, it is in the process of local naturalization in the Iberian Peninsula ( Portugal and Spain: Bartoli et al. 2007, Giraldo-Cañas 2008) where it is found as a weed of irrigated lawns and in riparian meadows, on wet sand. In mainland Portugal, it has been known since the 1960’s but the species was initially erroneously assigned to the morphologically similar A. affinis Chase ( Almeida 1999) . Claims of the latter from the Azores ( Menezes de Sequeira et al. 2012) are probably also referable to A. fissifolius (Euro+Med Plantbase 2023).

In the island of Madeira, Axonopus fissifolius was first identified in April 2022 in the Quinta do Palheiro estate, in Funchal, where it grows as a weed in lawns and between cobble stones; it looks firmly established. In this area, several other exotic grasses have been recorded in the past, e.g. Nassella neesiana (Trin. & Rupr.) Barkworth , N. trichotoma (Nees) Hack. & Arechav. and Rytidosperma tenuius (Steud.) O.E. Eriks. , A. Hansen & Sunding. At least the former is naturalized and quite abundant.

Axonopus fissifolius is much reminiscent of another weedy congeneric species, A. affinis , and both are often confused. The plants recently found in the island of Madeira have glabrous nodes, relatively narrow leaves 2–4 mm wide, spikelets up to 2 mm long and obtuse at apex, equaling the lemma. These characters point to A. fissifolius .