Robinia L.

Legumes of the World. Edited by G. Lewis, B. Schrire, B. MacKinder & M. Lock. Royal Botanic Gardens, Kew. (2005)

Note

The treatment of Polhill & Sousa (1981) recognised 21 genera and c. 145 species in Robinieae. This treatment, following modifications of Lavin (1988, 1993, 1995), Lavin & Sousa (1995), Polhill (1994), Lavin et al. (2003), reduces the tribe to 11 genera and c. 72 species (Fig. 52).

The phylogenetic positions of genera in Robinieae (excluding Sesbanieae) have largely remained the same since Lavin & Sousa (1995), although recent phylogenetic analysis of molecular (ITS/5.8S, trnL intron and matK locus) and morphological data merit further modification (Lavin et al., 2003). The Cuban Hebestigma is well supported as sister to the Mesoamerican Lennea in the combined analysis of Lavin et al. (2003), and in most analyses the two genera are sister to the Gliricidia and Robinia groups. Within the monophyletic Gliricidia group, Gliricidia is now demonstrated to be paraphyletic with respect to Hybosema, so the two are amalgamated. The Gliricidia group still includes the Antillean Poitea together with Gliricidia.

The monophyletic Robinia group comprising the ‘barbistyled’ genera, Olneya, Robinia, Coursetia, Peteria, Genistidium and Sphinctospermum, is sister to the Gliricidia group in most analyses of Lavin et al. (2003), although this is not strongly supported. The only significant modification within the Robinia group is that four eclectic species, Coursetia hypoleuca (Speg.) Lavin and C. orbicularis Benth. (unifoliolate species formerly composing the genus Poissonia), along with the Peruvian C. weberbaueri Harms and the Argentine-Bolivian C. heterantha (Griseb.) Lavin (formerly composing the monotypic Neocracca) form a well supported monophyletic group, here referred to as Poissonia, which in the analyses of Lavin et al. (2003) is either sister to Robinia or to Sphinctospermum.

Related (as the Robinia group of Lavin, 1995) to the S American Poissonia, although with low bootstrap support (Lavin et al., 2003)

Habit

Trees and large shrubs

Ecology

Cool to warm temperate montane regions in Appalachia to subtropical SW USA-NW Mexico in seasonally dry woodland, mostly as thickets at forest edges, often on rocky hillsides, road cuts, and along stream banks

Distribution

USA and NW Mexico; some species widely cultivated

Use

Robinia pseudoacacia L. (black locust) and R. hispida L. (bristly locust) are widely cultivated as ornamentals, both are root suckering and the former, especially, establishes itself aggressively in many areas; a number of hybrids and many cultivars exist. Other uses include soil enrichment and stabilisation, wood (construction, implements and crafts), fuelwood, human food and beverage (seeds, pods and flowers; a tea is infused from the bark) but care is necessary as plants have toxic properties, medicine, bee food (honey), bark fibre (textiles and paper), essential oils and dyes