Overview of the generic status of Acacia (Leguminosae: Mimosoideae)
Maslin, B. R.
Miller, J. T.
Seigler, D. S.
Australian Systematic Botany
2003
2003-12-31
16
1
18
[777,1220,307,330]
Magnoliopsida
Fabaceae
Acacia
CoL
Plantae
Fabales
11
12
Magnoliopsida
section
Filicinae
Aculeiferum
( 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. Filicinaeis 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. Filicinaesuggest 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. roseiand A. chamelensishad a sister group relationship to A. tequilana, with A. angustissimacompleting the well-supported clade.
The section may be characterised in the following ways (see Table 4for 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.