Mimosa dalyi Barneby

Margoth Atahuachi, M. Leontien Van Der Bent, John R. I. Wood, Gwilym P. Lewis & Colin E. Hughes, 2016, Bolivian Mimosa (Leguminosae, Mimosoideae): three new species and a species checklist, Phytotaxa 260 (3), pp. 201-222 : 213

17. Mimosa dalyi Barneby

Even with various new collections and localities (J.R.I. Wood et al. 24697 from Santa Barbara, NW of Roboré, LPB, K, USZ; J.R.I. Wood et al. 25140, Meseta Serranía del Mirador, LPB, K, USZ; D. Soto & Moreno 973, Serranía de Santiago, USZ; J.R.I. Wood 16487, Cerro Pelón, Chochis, LPB, K, USZ; M. Nee 37871, LPB, NY, USZ, Aguas Calientes; J.R.I. Wood & Pozo 26066, Ipias to La Ramada, LPB, K, USZ), this species remains narrowly restricted within eastern Bolivia [known only from 2 lat/long degree squares] and was, until recently, thought to be endemic to Bolivia. However, it has recently also been recorded from a single locality in north-eastern Paraguay ( Morales & Fortunato 2013). Within Bolivia, the species is apparently increasing in abundance and spreading following disturbance, forming roadside thickets in some areas ( Wood 2011).

These new collections, and especially specimens from around Taperas and Valle de Sonsas, including J.R.I. Wood et al. 24309, M. Saldias 5317, and Fuentes 1780, suggest that the leaf formula of M. dalyi as originally described by Barneby (1984, 1991), should be more broadly defined as follows: Leaf rachis including petiole (8–) 10–15 (–17) cm, petiole (5–) 8–10 (–17) cm, interpinnal segments 4–6.5 (–10) mm, pinnae (10–) 18–22 (–31) jugate, pinnular rachis 3.5–4.5 (–7) cm, leaflet length 2.5–4 (–6) mm. Such is the range of quantitative leaf variation within Bolivian M. dalyi , that it has been suggested that the closely allied M. insignis (Hassler) Barneby, which is endemic to the east side of the Rio Paraguay on the border between Mato Grosso do Sul and Paraguay, also occurs in Bolivia. However, even with this broader definition of leaf traits, these two species can still be separated based on leaf formula alone, as well as the presence of spicules on the leaf rachis of M. insignis.