Monographs Details: Cojoba zanonii (Barneby) Barneby & J.W.Grimes
Authors:Rupert C. Barneby
Authority: Barneby, Rupert C. & Grimes, James W. 1997. Silk tree, guanacaste, monkey's earring: A generic system for the synandrous Mimosaceae of the Americas. Part II. , , and . Mem. New York Bot. Gard. 74: 1-149.
Family:Mimosaceae
Synonyms:Obolinga zanonii Barneby, Pithecellobium micranthum Benth.
Description:Species Description - Broad-crowned microphyllidious trees 4-15 m with trunk attaining 1 m dbh, the lf- and inflorescence-axes sordidly puberulent with hairs to 0.2-0.4 mm, the lfts glabrous or minutely ciliolate, the capitula of small whitish fls solitary in lf-axils of homotinous branchlets. Stipules triangular-cupulate 0.4-1.2 mm, either deciduous or persistent as lignified points. Lf-formula (iii-)iv-viii(-ix)/16-27; lf-stk of larger lvs 3.5-10 cm, the petiole 5-13 mm, the longer interpinnal segments 5-16 mm, the ventral groove continuous or weakly bridged; nectary contiguous to first pinna-pair cupular thick-rimmed 0.7-1.3 mm diam, random similar but smaller nectaries between some or all distal pairs; pinnae proximally shorter, the rachis of longest ones ±40-65 mm, the longer interfoliolar segments 1.5-2.5 mm; lfts subsessile, decrescent at very ends of pinna- rachis, elsewhere subequilong, the blades narrowly lance-oblong from semicordate base, apiculate, either straight or a little curved forward, the longer ones (4.5-)5-9 x 1.4-3 mm, ±3-4 times as long as wide, all veinless or almost so above, beneath carinate by midrib forwardly displaced to divide blade ±1:2,1-2 short posterior primary nerves sometimes faintly raised or discolored beneath. Peduncles (2.5-)3.5-6.5 cm, 1-bracteolate shortly below capitulum, the receptacle globose 2-2.5 mm diam; bracts 0.5-0.7 mm, tardily deciduous; fls homomorphic 5-merous, the perianth glabrous except for minutely puberulent calyx-teeth and corolla-lobes; calyx campanulate short-toothed ±2.3-1.3 mm; corolla subcylindric 5-6.5 mm, the erect, ovate, often unequal lobes 0.7-1.5 mm; androecium 30-35-merous 9.5-11 mm, the included tube 3-3.5 mm; ovary sessile, glabrous at anthesis, 11-15- ovulate. Pods mostly solitary, pendulous, sessile, shortly cylindric or a trifle compressed, straight or slightly decurved 4.5-8(-9) x (1.6-)1.8-3(-3.8) cm, the reddish valves fleshy smooth but yellowish- puberulent overall, prior to dehiscence 2-5 mm thick in section, withering brown leathery wrinkled glabres- cent and only ±1 mm thick, dehiscent after falling by separation along the ventral or along both sutures, the cavity continuous; seed-funicles lance-ovate ±3 mm; seeds transverse, stacked broadside in a cylindric file, the one at each end of the cavity bluntly conical, the rest discoid (some not fully discoid), in broad view 20-28 mm diam, at the flattened periphery 4-8 mm thick, the thinly papery testa at first smooth lustrous brown but wrinkled and dull after exposure, on each face 4-nerved, lacking pleurogram.

Distribution and Ecology - In disturbed cloud forest, 1400-1900 m, localized on and near the crest of Massif de la Selle in S Haiti (dept, de l’Ouest) and Sa. de Bahoruco in SW Dominican Republic (Barahona). - Not mapped. - Fl. V-VIII; fr. VI-I.

Discussion:

Cojoba zanonii and C. bahorucensis, next following, closely resemble each other in persistence of some stipules as lignified conic points, 4-nerved seed-testa, and for an idiosyncratic fruit more like that of C. filipes: sausage-shaped, nearly terete fruit stuffed with obese seeds, these horizontal to the fruit’s long axis on (in C. zanonii) lance-ovate funicle and compressed into discs as wide as the pod-cavity (20-28 mm) but only 4-8 mm thick.

The status of Obolinga as originally proposed has become untenable. The phylogenetic analysis (Fig. 3) shows C. zanonii to be a derived member of Cojoba. Its fruit, unique when first described, is now known also in C. bahorucensis; the peculiar coinlike seeds can be viewed as the fulfillment of a trend toward hypertrophy of the embryo initiated in C. filipes. Studies of the pollen by P. Guinet and of wood by R. B. Miller, published immediately following the protologue, demonstrated close similarity in these features between Cojoba sensu stricto and C. zanonii. Nevertheless, C. zanonii, C. bahorucensis, and C. zanonii, all endemic to Hispaniola, remain, even without evidence from the fruit, extremely distinct in ecology, in leaf-formula, and in flower-size.

Distribution:Haiti South America| Barahona Dominican Republic South America|

Narratives:Cojoba zanonii
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