Mimosa falconis

  • Title

    Mimosa falconis

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Mimosa falconis Barneby

  • Description

    192. Mimosa falconis Barneby, sp. nov., M. invisae var. tovarensi proxime accedens, sed foliorum formula simplifacta, pinnis 2-4-, foliolisque 9-16(-17)-jugis usque plane diversa.— Venezuela. Edo. Falcón, distr. Bolívar: limestone ridges 2-4 km w. of Carrizalito, 11°08'N, 69°46'W, 19.X. 1985 (fl, fr), H. van der Werff (with R. Wingfield) 7466. —Holotypus, MO; isotypi, K, MEXU, NY.

    Microphyllidious shrubs attaining ± 1.5 m, the virgate, strongly ribbed stems armed near and between nodes with scattered, erect or subdeclined aculei 0.5-2.5 mm, the stems, lf-stks and peduncles in addition minutely puberulent and livid-granular, the lvs moderately bicolored, the facially glabrous lfts dark-olivaceous above, paler beneath, sometimes minutely ciliolate, the oblong-ovoid capitula all or mostly axillary to coetaneous lvs, the fruits immersed in foliage. Stipules erect, narrowly triangular-acuminate 2-3.5 x 0.5-0.9 mm, 1-nerved, persistent. Leafstalks 1.5-4 cm, the petiole including pulvinus 7-20 mm, at middle 0.5-0.6 mm diam., the longer interpinnal segments 4-8 mm, the ventral sulcus continuous between pinna-pairs (spicules 0); pinnae 2-4-jug., subaccrescent distally, the rachis of distal pair 9-22 mm, the longer interfoliolar segments 0.5-1.5(-2) mm; lfts of longer pinnae 9-16(-17)-jug., the first pair 0.4-1.7 mm distant from lance-ovate paraphyllidia 0.3-0.6 mm, the blades linear-oblong from shallowly semicordate or obtusangulate base, obtuse or obscurely deltate-acute at apex, the longer ones 4— 6.5(-8) x 1.2-2(-2.4) mm, 3-4.3 times as long as wide, all veinless above, beneath weakly 2-nerved from pulvinule, the scarcely displaced midrib either simple or finely 2-3-branched on each side, the posterior nerve either weak and short or camptodrome near mid-blade, the nerves all immersed but discolored. Peduncles solitary and fasciculate by 2-4, 7-15 mm; capitula oblong-ovoid, without filaments ±4-5 mm diam., prior to anthesis moriform, the obtuse fl-buds either glabrous or minutely puberulent, the receptacle becoming 3-6 x 0.8-1 mm; bracts oblanceolate 0.5-0.6 mm, deciduous; flowers sub-dimorphic, the lowest smaller and some of them sometimes 4-merous staminate, the distal ones or sometimes all 5-merous bisexual, all haplostemonous; calyx membranous campanulate 0.4-0.5 mm, the orifice obscurely crenulate and microscopically granular-ciliolate; corolla of middle and upper fls ±2-2.5 mm, turbinate-campanulate but contracted proximally, the erect lance-ovate acute 1-nerved lobes 0.8-1 x 0.40.6 mm; filaments pink-lilac, free, exserted 3.5-5 mm; anther-connective longer than wide. Pods 1-4 per capitulum, sessile or basally attenuate, in profile broad-linear straight or almost so, planocompressed 30-85 x 8-10 mm, 6-10-seeded, the replum 0.4-0.55 mm diam., constricted only where ovules abort, unarmed or charged on seminiferous suture with 1-2 small prickles, the papery, green or brownish-stramineous valves low-colliculate over each seed but otherwise plane, the replum and valves minutely granular and sometimes also minutely puberulent, the valves breaking up into free-falling articles 4.5-8 mm long; ripe seeds not seen.

    In open scrub-woodland, sometimes on limestone, near 1300 m, known with certainty only from Sa. de S. Luis in state of Falcón and from "Loma de León," distr. Tribarren in state of Lara, Venezuela.—Fl. IX-XI(-?). Map 27.

    Mimosa falconis has essentially the flowers and fruits of M. invisa var. tovarensis, but differs from M. invisa sens. lat. in notably reduced leaf-formula. Its ultimate taxonomic status will depend on stability of the formula within populations that conform to a natural pattern of dispersal and on the value attached to these criteria.