Mimosa extranea

  • Title

    Mimosa extranea

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Mimosa extranea Benth.

  • Description

    112. Mimosa extranea Bentham, Trans. Linn. Soc. London 30: 433. 1875.—"San Domingo, communicated by Jacquemont to the Berlin herbarium."—Holotypus, collected (Urban, Symb. antill. 3: 106. 1902) near Gonaïves in Haiti by French vice-consul Prax, +B.—No isotypus found, but the protologue unmistakable.— Haitimimosa extranea (Bentham) Britton & Rose, N. Amer. Fl. 23: 179. 1928. Fig. 8.

    M. extranea sensu Urban, Symb. antill. 2: 268. 1900; 8: 259, 1920; Rose & Leonard, 1927: 256; Liogier, 1985: 49.

    Stiffly densely branched shrubs or treelets 1.5-3 m with most or all lf-stks dilated into subcoriaceous linear simple phyllodia, unarmed or randomly armed at some nodes and at tip or on margins (exceptionally on midrib) of some phyllodia with recurved aculei 0.5-1.5 mm, the young growth minutely puberulent and minutely livid-granular, the globose capitula solitary and paired in axils of primary lvs and of smaller lvs on axillary branchlets. Stipules subulate 0.2-0.5 mm, caducous. Leaf-stalks transversely dilated 25- 60(-70) x (1.5-)2-6 mm, cuneately attenuate at base, obtuse-mucronulate at apex, commonly 3- or the broader ones 5-nerved, all without lfts or some when young with a terminal pair of pinnae, these each 2- or rarely 4-foliolate, their rachis 2-7 mm, the firm plane glabrous lfts elliptic obtuse ±2.5-5.5 x 1.5-3, veinless, caducous. Peduncles 6-38 mm; capitula without filaments ±5 mm diam., prior to anthesis moriform, the obtuse fl-buds gray-puberulent; flowers 4-5(one seen by Bentham reportedly 3)-merous diplostemonous, all bisexual; calyx narrowly campanulate 0.8-1 x 0.5 mm, puberulent externally, the triangular teeth ±0.2 mm; corolla trumpet-shaped 2.4-3 mm, the spreading ovate pinkish nerveless lobes 0.8-1.3 x 0.5-0.7 mm; filaments white, united at very base to corolla, exserted 2.5—3 mm; ovary puberulent. Pods ±2—5 per capitulum, subsessile, cuneately contracted at base, in profile sinuately linear 30—45 x 6—6.5 mm, 6—8-seeded, the shallowly constricted replum 0.3—0.5 mm wide, produced at apex into an erect cusp 1.5—4 mm, either smooth or randomly armed with few recurved aculei 0.5—1.5 mm, the stiffly papery lustrous red- or purple-brown glabrous valves low-colliculate over each seed, when ripe breaking up into free-falling, tardily dehiscent articles 4.5-5.5 mm long; seeds discoid ±3 mm diam., the testa dull brown.

    In xeromorphic shrub communities, near sea-level to 650(-?) m, locally abundant in departements du Nord-Ouest and de l’Artibonite in n.- w. Haiti.-Fl. XI-I, VI-?

    Bentham saw only a small branchlet of this curious Haitian endemic and, probably not aware that it is a shrub of considerable stature, mistakenly associated it with the weak herbaceous M. paucifolia and M. phyllodinea native to the Brazilian Planalto. It appears certain that M. extranea is related closely and directly to compatriot Fagaracanthae such as M. domingensis, to which it is firmly linked by M. leonardii. Loss of leaflets and compensatory expansion of the leaf-stalk has occurred independently in so many genera of Leguminosae, both woody and herbaceous, that it would be absurd to accord it generic recognition in the absence of supporting characters. Thus, Haitimimosa is one of Britton’s less felicitous proposals; H. extranea has flowers, fruits and even random foliaceous leaves entirely typical of Mimosa.