MIMOSACEAE. 161 



style filiform. Pod woody, swollen, nearly terete, very tardily dehiscent or inde- 

 hiseent, pulpy within. Seeds in two rows, immersed in the pulp. [Com- 

 memorates C. H. Vac-hell, an English missionary and botanical collector in 

 China.] A monotypic genus. 



>< 1. Vachellia Farnesiana (L.) W. & A. Prodr. 272. 1834. 



Mimosa Farnesiana L. Sp. PI. 521. 1753. 

 Acacia Farnesiana Willd. Sp. PL 4: 1083. 1806. 



A shrub or small tree up to about 9 m. high, its thin brown bark scaly, 

 the slender branches spreading, the twigs armed with stiff paired whitish 

 spines 1-2.5 cm. long. Leaves glabrous or more or less pubescent, evenly bipin- 

 nate, 4-8 cm. long, short-petioled ; pinnae 3-8 pairs, sessile or nearly so; 

 leaflets 10-25 pairs, linear-oblong, 2-6 mm. long, bluntish at the apex; 

 peduncles axillary, slender, mostly shorter than the leaves; heads 8-12 mm. in 

 diameter; flowers yellow, fragrant; calyx about half as long as the corolla; 

 corolla about 1.5 mm. long; stamens 2-3 times as long as the corolla; pod 

 straight or a little curved, 3-7.5 em. long, about 1.5 cm. thick, pointed, dark 

 brown; seeds shining, 6 mm. long. 



Waste and schub-lands and coastal thickets, Andros, New Providence, Eleuthera, 

 Cat Island, Watling's, Great Exuma, Fortune Island. Grand Turk and Caicos : 

 Florida; Cuba to Virgin Gorda and Tobago; Jamaica: continental tropical Amer- 

 ica and Old World tropics. Recorded by Dolley as Acacia tortuosa* Willd., a Jam- 

 aican species. Aroma. Cashia. Opoponax. 



7. MIMOSA L. Sp. PI. 516. 1753. 



Herbs, shrubs or rarely trees, mostly with 2-pinnate, often sensitive leaves, 

 the small regular, mostly 4-5-parted, perfect or sometimes polygamous flowers 

 in axillary, peduncled heads or spikes. Calyx small, its teeth short. Petals 

 valvate, connate below, hypogynous. Stamens as many as the petals or twice as 

 many, distinct; exserted; filaments mostly filiform; anthers small, eglandular. 

 Ovary 2-many-ovuled ; style slender or filiform; stigma terminal, small. Pod 

 linear or oblong, usually flat, often transversely jointed, 2-valved with the con- 

 tinuous margins persistent. Seeds compressed. [Greek, referring to the sensi- 

 tive leaves of some species.] Over 300 species, natives of tropical and warm 

 regions. Type species: Mimosa sensitiva L. 



Low, sensitive-leaved herb. 1. If- pudica. 



Shrub, the leaves not sensitive. 2. M. bahamensis. 



1. Mimosa pudica L. Sp. PI. 518. 1753. 



Herbaceous, or a little woody, loosely pubescent with long hairs or gla- 

 brate, branched, 5 dm. high or less, the stems and branches armed with rather 

 stout, somewhat curved prickles 2-4 mm. long. Stipules lanceolate, striate, 

 acuminate, 3-6 mm. long; petioles slender, with a pulvinus at the base, 2-6 

 cm. long, deflexed when touched; pinnae 1 pair or 2 approximate pairs, also 

 with a pulvinus at base, 2-6 cm. long; leaflets 15-25 pairs, thin, linear, 6-10 

 mm. long, 1.5-2 mm. wide, folding when touched, acutish at the apex, obliquely 

 rounded at the base; heads ovoid, axillary; peduncles 1-2 cm. long; calyx 

 minute; petals and stamens 4; stamens pink; pods linear-oblong, 2-5-jointed, 

 1-1.5 cm. long, 3 mm. wide, constricted at the joints, the margins armed with 

 slender straight prickles, otherwise glabrous. 



Andros at Mastic Point, collected only by Keith: West Indies; continental 

 tropical America : naturalized in the East Indies. Cultivated on New Providence. 

 Sensitivh Plant. 



