Monographs Details: Mimosa monadelpha Chodat & Hassl.
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:Species Description - Erect unarmed subshrubs 5—10 dm, the stems at anthesis defoliate toward base, densely foliate and usually branched distally into a pyramidal panicle of subglobose capitula, the stems, lf-stks of palmatipinnate lvs and all axes of inflorescence commonly densely gray-puberulent and pilose with fine, either shorter ascending or longer spreading, lutescent setae to 1-2 mm long and at base to 0.1-0.15 mm diam., rarely nearly glabrous throughout, the dried foliage dull dark brown, the thin-textured lfts subconcolorous or livid beneath, glabrous on both faces, discontinuously setose-ciliate, the capitula mostly axillary to coevally expanding lvs, some late ones shortly pseudoracemose. Stipules narrowly lance-attenuate 4-7 x 0.5-0.75 mm, strongly 1-nerved, either puberulent or glabrous dorsally, setose-ciliolate, persistent. Petiole of primary cauline lvs 1-3 cm, at middle 0.65-1.4 mm diam., that of some smaller rameal lvs shorter; pinnae of larger lvs 3-4-jug., of some diminished distal lvs 2-jug. (no further described), the pairs of pulvini subcontiguous, the lf-rachis 2-4 mm; rachis of longer pinnae 3.5-7 cm, the longer interfoliolar segments 1.5-3 mm; lfts of longer pinnae 24-32- jug. (of lowest lvs often fewer), decrescent proximally, the small unequal first pair 0.1-0.5 mm distant from subulate paraphyllidia 0.3-1.3 mm, the blades narrowly oblong from obtusangulate base, abmptly apiculate, those at and beyond mid-rachis 4.5-12 x 1.2-3.5 mm, 3—4.3 times as long as wide, all weakly (2-)3-5-nerved from pulvinule, the simple midrib displaced to divide blade 1:1.5-2, the inner posterior nerve expiring beyond mid-blade, the outer ones much shorter, the venation on upper face fully immersed and often imperceptible, on lower face either discolored or faintly raised. Peduncles solitary or occasionally geminate (7-) 10-29 mm; capitula without filaments 6.5-8 mm diam., prior to anthesis moriform, the receptacle glabrous, the 4-sulcate fl-buds microscopically papillate at tip; bracts linear or linear-spatulate 1.4-2.4 x 0.25-0.4 mm, 1-nerved and glabrous dorsally, setulose-ciliolate toward tip; flowers 4-merous 4-androus, some proximal ones staminate and smaller; calyx paleaceous pallid (1-) 1.3-1.9 mm, the glabrous brown tube 0.2-0.3 mm, the lobes deeply decompound; corollas narrowly funnelform (2-)2.3-3 mm, the comeously thickened cymbiform lobes 0.8-1.1 x 0.5-0.65 mm; filaments pink, monadelphous through 1.2-1.4 mm, exserted 4.5—6.3 mm. Pods ±2—6 per capitulum, sessile, in profile oblong 12-24(-25) x 5.5-7.5 mm, broadly rounded at each end, mucronulate at apex, 2-4-seeded, the shallowly constricted replum 0.3—0.8 mm wide, either densely setose with pluriseriate ascending stramineous setae to ±1.5 mm or appressed-setulose, the papery valves either densely hispid with similar but more widely incurved-ascending setae to ±3 mm or only thinly strigose, when ripe breaking up into free-falling, individually dehiscent articles 3-5.5 mm long; seeds (few seen) transverse, compressed-rhomboid-obovoid, in wide profile ±4.5-6 x 3.5—4.5 mm, the smooth testa lustrous brown.

Discussion:

Mimosa monadelpha is closely akin to M. lupinoides, but has stems twice as tall, has six to eight rather than exactly four pinnae borne subpalmately at tip of each leaf-stalk, and has nearly twice as many leaflets per pinna, these only about half as wide. Two readily distinguishable pubescence forms have been described.