Zygia macbridii

Title

Zygia macbridii

Authors

Rupert C. Barneby

Scientific Name

Zygia macbridei (C.Barbosa) L.Rico

Description

30. Zygia macbridii (Barbosa) L. Rico, Kew Bull. 46: 501 ("macbridei," the altered spelling unexplained and unjustified). 1991. Pithecellobium macbridii Barbosa, Caldasia 14: 398. 1986. — "PERU, Loreto, Mishuyacu, cerca a Iquitos . . . Oct-Nov 1929, G. Klug 572 fl." — Holotypus, NY!; isotypus, F n.v.

Macrophyllidious cauliflorous trees 4-11 (-15) m, glabrous except for the inflorescence and fruit, the ample, stiffly chartaceous lfts brownish-olivaceous, scarcely paler beneath, the short fl-spikes fasciculate on knots of annotinous branchlets and older branches. Lf-formula i/1½, the lfts 6 per lf, the odd proximal posterior lft of each pinna about half as long as the terminal pair and inserted well below mid-rachis, often close above the pinna-pulvinus; petioles 1-9 x 2.5-4.5 mm, often as broad as or even broader than long; nectary between pinna-pulvini sessile, round or deltate, plane 1.7-2.6 mm diam, and a similar one between each terminal pair of pulvinules; rachis of pinnae (3-)4-7.5 cm; lft-pulvinules in dorsal view 3.5-7 x (1—)1.7—3.5 mm; lfts elliptic, either shortly or attenuately acuminate at each end, the distal pair (12-) 14-24 x 5-8.5 cm, 2.3-3.8 times as long as wide; venation pinnate, the almost straight midrib centric or almost so, giving rise on each side to 5-8 major (and random intercalary) secondary nerves in- curved-ascending and feebly brochidodrome well within the plane margin, the first 2-3 on posterior side of midrib either scarcely or perceptibly stronger than succeeding ones, the connecting tertiary and reticular venulation random and weak. Spikes subsessile, ±7-25-fld, the axis 9-26 mm; bracts 0.8-1 mm, persistent; perianth whitish, finely minutely strigulose overall, the calyx externally nerveless, the corolla only weakly or not externally nerved (not striate); calyx campanulate (1.4) 1.8-3.5 x 1.2-1.8 mm, the depressed teeth 0.2-0.4 mm; corolla either tubular or moderately dilated in distal third, the erect, ovate-triangular lobes 1-1.7 mm; androecium ("30"-)- 32-33-merous 21-24.5 mm, the tube 10-13 mm, exserted 1-3.5 mm, the tassel pink or lilac-purple; intrastaminal disc 0.45-1.7 mm; ovary at anthesis glabrous, symmetrically conic at apex; stigma poriform 0.2 mm diam. Pods pendulous from the trunk or branch, sessile, in profile oblong or broad-linear 4.5-11 x 2.3-2.8 cm, obtuse apiculate, straight or slightly decurved, 2-7-seeded, planocompressed becoming low-convex over seeds and shallowly depressed between them, the thick, rigidly pithy-ligneous valves framed by obtusely prominulous sutures, the ventral suture sulcate lengthwise, the ripe valves brown, densely minutely pilosulous-tomentulose overall; dehiscence of the genus; seeds obese, contiguous and mutually deformed, ±2 cm diam and nearly half as thick.

In moist forest but often above the floodline, 100-230 m, apparently localized in the upper Amazon basin in SW prov. Maynas, adj. prov. Requena, and prov. Alto Amazonas, Peru. — Map 27. — Fl. VIII, X-II. — Shimbillo.