Zygia ramiflora (F.Muell.) Kosterm.
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Authors
Rupert C. Barneby
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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
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Scientific Name
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Type
"Borba, in Brazil [Riedel, commun.] Langsdorff." — Holotypus, K (hb. Bentham.)! = NY Neg, 2029; isotypus, NY!. — Marmaroxylon ramiflorum (Bentham) L. Rico, Kew Bull. 46: 518. 1991.
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Synonyms
Marmaroxylon ramiflorum (Benth.) L.Rico
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Description
Species Description - Macrophyllidious unarmed trees, fertile at (3-) 4-10 m but potentially 30 m tall, with pallid annotinous branches, the leaf- and inflorescence-axes pilosulous with yellowish-brown hairs 0.15-0.4 mm, the leaves bicolored, the papery-membranous leaflets dark olivaceous, smooth and somewhat lustrous above, paler beneath, the short spikes of fragrant white fls mostly fasciculate directly on efoliate brachyblasts, or very shortly paniculate from knots on defoliate stems below the hornotinous foliage, or randomly axillary to a few older lvs. Stipules ovate or lanceolate 1-3.5 mm, early dry deciduous, sometimes slenderly costate but not striately nerved externally. Lf-formula (i—)ii—v/(5—)6—9(— 10); lf-stk of major lvs (1.5-)3.5-10(-14) cm, the true petiole often reduced to the stout pulvinus, at most 6(—13) mm long, the longer interpinnal segments ±2-5 cm; a sessile, shallowly cupular thick-rimmed nectary 1.4-2.8 mm diam immediately below first pinna-pair, smaller ones often at insertion of some further pinna-pairs, and yet smaller ones on pinna-rachises between 2-3 further pairs of lfts; pinnae strongly accrescent distally, the short first pair sometimes deciduous from small scars, the rachises of furthest pair (5—)7—13 (-15) cm, the longer interfoliolar segments 8-25 (-33) mm; lft-pulvinules obese, 0.5-1.4 x 0.7-1.4 mm; lfts strongly accrescent upward from short first pair (these sometimes reduced to paraphyllidia), the blade of median and distal ones inequilaterally rhombic-elliptic or -oblong from proximally blunt-auriculate base, either shortly obtusely or attenuately acuminate and at very apex minutely apiculate, the penultimate pair 3.5- 9.5(-14) x (1.3-)1.5-3.5(-5.5) cm, 2.2-3.2(-4) times as long as wide, the furthest pair usually a little longer and less oblique; venation weakly palmate at very base and thence pinnate, the slender subcentric, distally incurved midrib sharply prominulous on both faces, giving rise on each side to 6-11 (-12) weak, widely ascending (and indefinite fainter intercalary) secondary nerves brochidodrome shortly within the plane margin, an irregular reticulum of veinlets sometimes perceptible dorsally. Spikes ±15-40-fld, the axis including short or obsolescent peduncle 6-20 mm; bracts deltate acute 0.7-1.1 mm, persistent; fls sessile ascending; perianth 5-merous, the calyx brown-gold- puberulent beyond middle, sometimes overall, the corolla either puberulent overall or only the lobes minutely so; calyx deeply campanulate 2-3 x 0.9-1.6 mm, the depressed-deltate teeth 0.2-0.4 mm; corolla subcylindric 6.3-7.5 mm, the erect, often unequal lobes 0.8-2 x 0.6-0.9 mm; androecium 20-42-merous, 14.5-18.5(-25) mm, the stemonozone 0.8 mm or less, the tube 7.5-9.5(-10.5) mm, exserted 1 mm or more; ovary sessile, narrowly ellipsoid, conic at apex, at anthesis glabrous but densely tomentellous following fertilization, surrounded at base by a shallowly lobed disc 0.35-0.7 mm tall. Pods sessile, in profile linear, falcately or only slightly decurved, 8-11.5 x 1-1.1 cm, 8-17-seeded, strongly compressed, the almost flat, stiffly leathery valves framed by dilated sutures 1.5-3 mm wide and constricted if at all only where ovules abort, the ripe valves obscurely colliculate over seeds, externally evenulose, densely brown-tomentellous overall, internal septa 0; dehiscence not surely known, apparently folliculate, the epicarp sometimes cracking transversely between seeds but firmly attached to sutures, the endocarp smooth, reddish brown and resinous within the seed cavities, brownish between them; seed-funicle compressed, sigmoid; seeds obliquely basipetal, compressed-ellipsoid ±8x6 mm, the papery testa girdled by peripheral nerve, sub- diaphanous at middle of each seed-face, loosely investing the green embryo; pleurogram 0.
Distribution and Ecology - In terra firme forest, Amazonian caatinga, and campirana, below 250 m, scattered through middle and upper Amazonia in Brazil (Amazonas, Acre, and Rondônia), adj. Peru (Loreto), and SW Venezuela (T. F. Amazonas), thence weakly N into the upper Orinoco basin (lower Río Ventuari); perhaps (see discussion) also distantly disjunct in Pacific Colombia (Valle). — Map 23. — Fl. IX-XII, V.
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Discussion
Zygia ramiflora is related most closely to Z. collina and Z. transamazonica. It differs from Z. collina somewhat precariously in lower leaf-formula, but Z. transamazonica seems more substantially distinct in perfectly glabrous foliage and lack of petiolar nectaries. Full comparisons must be postponed, however, until the fruits of these two relatives are known.
We find Z. ramiflora inconveniently labile in number of pinnae per leaf, less so in size and number of leaflets, and moderately so in pubescence of the perianth; but we have failed to trace significant correlations either among these features or between them and dispersal. The original P. ramiflora, from the lower Madeira valley at Borba, unknown to Ducke (1949: 45), has leaf-formula ii-iii/7-8 and larger leaflets to ±6-8 cm long; that of Pithecellobium umbriflorum, from the Solimões valley near 68°W, has leaf-formula ii-iv/7-9 and larger leaflets about 3.5 cm long; while that of P. dinizii, from the lower Trombetas basin at 54°W, has leaf-formula i-ii/7-8 and larger leaflets to 4 cm. A few modem collections have, with 2 to 4 pairs of pinnae, either as few as 6 leaflet-pairs to 9-10 cm long or as many as 10 pairs to 3 cm long, but most fall somewhere between those extremes. The type collection of Pithecellobium dinizii, of which Ducke saw only one individual tree, is unique in this context because of predominantly geminate (but some bijugate) pinnae combined with pink flowers. One other instance of geminate pinnae (L. S. Coelho 31, from mun. Oriximiná, Pará, NY) is known, but its flowers, like those of Z. ramiflora elsewhere, are white. However, both pink- and white- flowered forms are known in some other species of Zygia (e.g., Z. inaequalis, Z. collina), and the leaf- formula, although marginal, is not discontinuously separate. Pending discovery of the fruit, which could be surprising, it seems prudent to interpret Pithecellobium dinizii as a taxonomically insignificant variant of Zygia ramiflora.
A specimen (Cuatrecasas 16075, US) from the department of Valle in Pacific Colombia, unfortunately lacking fully expanded flowers, seems conspecific with Amazonian Z. ramiflora, but its identity requires confirmation from more mature material. The record is omitted from our map (Map 23). This Colombian zygia is locally known as pinchindé de monte.
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Common Names
Ingaí
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Distribution
Amazonas Brazil South America| Acre Brazil South America| Rondônia Brazil South America| Loreto Peru South America| Amazonas Venezuela South America| Valle Colombia South America|