Acacia wrightii Benth.

  • Authority

    Isley, Duane. 1973. Leguminosae of the United States: I. Subfamily. Mimosoideae. Mem. New York Bot. Gard. 25 (1): 1-152.

  • Family

    Mimosaceae

  • Scientific Name

    Acacia wrightii Benth.

  • Description

    Species Description - Thicket-forming, straggling, often suckering, glabrous to pubescent shrub .5-3 (-6) m high, usually armed with decurved, internodal prickles, mildly fragrant in bloom. Leaves mostly clustered (2-3) from spurs, bipinnate; petioles (-4)6-11 mm; leafstalk gland between lower pinnae usually capitate; pinnae 1-2 pairs; leaflets 2-6 pairs, elliptic-obovate to oblong, 5-9 (-12) mm, reticulate with midvein displaced. Flowers in cream-yellow, frequently loose racemes (3-) 5-6 cm. Legumes oblong, flattened, straight to curved, 5-15 cm long, 1.5-2.5 cm wide, straight-margined or somewhat constricted but not twisted; valves thick-papery, somewhat flexible, glabrous, often reddish tinted and glaucous, moderately expressed over seeds. Seed not circular, ca 1 cm in length.

  • Discussion

    Senegalia wrightii (Benth.) Britt. & Rose Acacia greggii var. wrightii (Benth.) Isely I previously (Isely, 1969) relegated A. wrightii to varietal status because of its vague demarcation from the almost entirely sympatric A. greggii, and uncertainty of non-fruiting material. However, although perversely more difficult to delimit from A. greggii var. greggii than from the weakly marked A. greggii var. arizonica, A. wrightii does differ from the former on a multicharacter basis. For this reason, at least theoretically sound, A. wrightii may reasonably be sustained as a species. Probably, there has been a partial or complete genetic isolation between A. wrightii and A. greggii plexus for some time, although I cannot suggest its nature. One can postulate that habitat disturbance by man has brought the two together and obscured specific lines. I am puzzled by the fact that the gatherings which I have been unwilling to assign to one or the other come from the northern periphery of the common range (Map 7).

  • Distribution

    W and s Texas. Brushy slopes to flood plains or washes; mesquite scrub; sandy to caliche soils (April)June-August. Catclaw. Mexico.

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