Acacia subg. Aculeiferum sect. Filicinae

Maslin, B. R., Miller, J. T. & Seigler, D. S., 2003, Overview of the generic status of Acacia (Leguminosae: Mimosoideae), Australian Systematic Botany 16, pp. 1-18 : 12

Acacia subg. Aculeiferum sect. Filicinae

( Fig. 6 )

A New World group comprising 15 species (L. Rico-Arce, pers. comm.) that extends from the south-central USA south to Argentina; the highest concentration of species occurs in Mexico. As noted above, molecular data suggest that sect. Filicinae is a distinct evolutionary lineage. This group was recognised by Britton and Rose as the genus Acaciella ( Britton and Rose 1928) . According to Pedley (1987), the morphological and chemical attributes of sect. Filicinae suggest that it could well be treated as a distinct genus; a similar view was expressed by Guinet (in Maslin 1987). Treated as a genus, this group would be called Acaciella . Robinson and Harris (2000) provided the only molecular insight into relationships within the Filicinae. They found that A. rosei and A. chamelensis had a sister group relationship to A. tequilana, with A. angustissima completing the well-supported clade.

The section may be characterised in the following ways (see Table 4 for further details): Trees, shrubs or suffrutescent perennials. Prickles absent. Stipules normally present, never spinose. Leaves bipinnate, with 1–25 pairs of pinnae; leaflets 3–60 pairs, 3–60 mm long. Petiolar glands absent. Inflorescence systems simple, racemose or paniculate; flowers arranged in globular or obloid heads, white-cream colored, 5-merous, drying a pink-brown color. Floral bracts linear, early deciduous. Ovary on gynophore; a nectariferous disk at the base of the ovary. Pods small, chartaceous, dehiscent. Funicle exarillate.

Figures

Fig. 6. Indicative distribution of distribution of Acacia sect. Filicinae.