Monographs Details: Mimosa claussenii var. soderstromii Barneby
Authors:Rupert C. Barneby
Authority: Barneby, Rupert C. 1991. Sensitivae Censitae. A description of the genus Mimosa Linnaeus (Mimosaceae) in the New World. Mem. New York Bot. Gard. 65: 1-835.
Family:Mimosaceae
Description:Variety Description - Diffuse shrubs attaining a spread of 2 m but a height of only 4-6 dm, the humifuse trunks to 2.5cm diam. giving rise to a few long, amply multipinnate subradical lvs and stout ascending flowering stems 1.5—4 dm, these leafless or almost so at anthesis but terminating in a tuft of hysteranthous foliage, the lf- and inflorescence-axes both hirsute and viscid-villosulous, the inflorescence a simple or few-branched pseudoraceme of large long-pedunculate subglobose capitula; leaf-formula (xxi-)xxiii-xxx/50-64, the lf-stks (2-)3-5 dm, the rachis of longer pinnae 7-10.5 cm, the longer lfts 5.5-9 x 1.2-2 mm; peduncles 7-15 cm; capitula without filaments 15-20 mm diam.; corolla (5.5-)6-8 mm; pods 30-47 x 16-18 mm, the replum 3-4.5 mm wide, the valves concealed by a coat of lustrous cream- colored setae to 3-4 mm.

Distribution and Ecology - Hillsides in cerrado, probably near 1000 m, locally common but known only from Distrito Federal at points 35 km e. and 20 km n.-e. of Brasília.-Fl. VII-IX.

Discussion:

The var. soderstromii has the capitula and pods of var. claussenii but is distinguished by peculiar growth-form described above, a partly glandular indumentum, and a modified rhythm of growth. At anthesis, which occurs in July and August, a few very large mature subradical leaves, apparently of the previous year’s growth, persist at tip of some annotinous branches, while from the tip of others arise short stout leafless axes bearing a succession of long-pedunculate and relatively large capitula. Subsequently this flowering axis bears beyond the flowers a tuft of hysteranthous leaves of which I have seen no example fully grown out. The growth-cycle deserves careful observation in the field.

I dedicate this odd but handsome mimosa to the late Dr. Thomas Soderstrom, agrostologist at the Smithsonian Institution, who accompanied Dr. Irwin in 1964.

Distribution:Brazil South America| Distrito Federal Brazil South America|