Rupert C. Barneby
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.
Mimosaceae
Feuilleea rufescens (Benth.) Kuntze, Inga rufescens Benth., Inga tubulifera Benth., Feuilleea tubulifera (Benth.) Kuntze, Inga billbergiana Benth., Feuilleea billbergiana (Benth.) Kuntze, Inga globulifera Benth., Feuilleea globulifera (Benth.) Kuntze, Inga dariensis Seem., Inga membranacea Benth., Feuilleea membranacea (Benth.) Kuntze, Cojoba membranacea (Benth.) L.Rico, Cojoba glabra Britton & Rose, Cojoba undulatomarginata L.Rico, Cojoba whitefoordiae L.Rico, Pithecellobium rufescens (Benth.) Pittier
Species Description - Amply foliate unarmed arborescent shrubs and trees (3-)4-15 m, with smooth gray bark, the new stems, lf-axes and peduncles nearly always pilosulous and the lf-buds tomentulose with either straight spreading or tangled incurved, yellowish or bronze hairs to 0.15-0.4 mm, the lvs simply paripinnate, the papery lfts bicolored, olivaceous and often sublustrous on upper face, paler on lower, usually glabrous except for puberulent midrib and sometimes puberulent secondary nerves but rarely (especially when young) thinly pilosulous on one or both faces and sometimes fully glabrate in age, the dense globose capitula of greenish white-stamened fls arising singly or in fascicles of 2-3 in or immediately above the axil of several coeval or new-fallen lvs, immersed in foliage. Stipules submembranous 1-nerved caducous, absent from many specimens, either triangular-subulate 0.5-1.5 mm or linear-lanceolate 2-5 mm. Lf-formula 0/(1-) 2-9; lf-stks (0.6-)2.5-16(-17) cm, the petiole (including or almost reduced to the stout pulvinus) 4.5-40 mm, usually much shorter and never longer than the longest interfoliolar segment, this 1.4-4.7 cm; a sessile, either round, elliptic or bluntly 3-angulate, either dimpled or cupular thick-rimmed nectary (0.3-)0.4-2 mm diam at insertion of each lft-pair; pulvinules (1-) 1.5-5 x 0.8-1.7 mm, cross-wrinkled; lfts strongly accrescent distally, either elliptic, broadly elliptic, ovate- or obovate-elliptic from subequilaterally cuneate or postically rounded base, either obtuse or very shortly bluntly acuminate, the furthest pair 5-36.5 x 2.2-11 cm, 1.7—4.5 times as long as wide; venation pinnate, the subcentric, either straight or gently porrect midrib giving rise on each side to 7-15 major (and random intercalary) secondary nerves widely ascending-incurved to anastomosis well within the undulately crisped or almost plane margin and then to a fine lax reticulum of venules, the whole venation sharply prominulous on lower face of lfts, less so on upper, or the major veins there shallowly depressed and the reticulum scarcely perceptible. Peduncles 4-50 mm, bearing near middle or close under the globose capitulum 1 (-2) ovate or linear-lanceolate bracts 1-6 mm, the subspherical receptacle ±2-4 mm diam, this charged either with more or less elongate linear- lanceolate or with shorter linear-spatulate, persistent bracts 1-5.5 mm, these either shorter than or far surpassing the immature fl-buds; capitula densely ±2580-fid, the homomorphic fls radiating in all directions, sessile; perianth 5-merous, thin-textured (fragile when dry), greenish, glabrous externally except for brown- puberulous tip of calyx-teeth and corolla-lobes; calyx either deeply narrowly campanulate or a little dilated beyond middle and turbinate-campanulate (1.3—) 1.5-3 x 0.8-1.6 mm, the often incurved, deltate, depressed-deltate, or subtruncate teeth 0.1-0.4 mm; corolla tubular, slightly dilated distally, 6.5-9.5 mm, the ascending ovate lobes 0.6-2 mm; androecium 15-32-merous, 10-18 mm, the stemonozone 0.6-1.25 mm, the tube (3.5-)4-7 mm, not callous at base; ovary (sub)sessile, narrowly oblong-ellipsoid, glabrous but sometimes micropuberulent after fertilization; style shortly exserted, the stigma poriform. Pods essentially as in C. arborea, either subterete and shallowly indented between seeds or (when longer) moniliform, 5.5-14 x 0.9-1.5 cm, 8-13-seeded, the black, plumply ellipsoid, at first lustrous but when dried dull and wrinkled seeds 8.5-11 x 6-7 mm.
Distribution and Ecology - In moist thickets and forest, on riverbanks and lake- or seashores, from near sea level to ±1600 (-2100) m, locally plentiful, centr. Costa Rica (San José) E through Panama, on the Pacific slope (except at the Isthmus) and off-shore islands, to N Chocó, Colombia. — Map 16. — Fl. primarily XI-V, but randomly at other times.
Cojoba rufescens is unique in the simply pinnate leaves, which are suggestive of Inga, though associated with the red moniliform dehiscent fruit of Cojoba. While readily recognized by its foliage, it varies greatly in number, size, and pubescence of leaflets, in length of floral bracts, and in length of peduncles; furthermore, it is at home both in lowland and coastal forest and, in western Panama and Costa Rica, at elevations to 2100 m on the south slope of the Cordillera, which suggests ecological differentiation. However, despite the number of names proposed for various forms, we have not found significant correlation between the variable features or between these and habitat, and therefore propose a comprehensive specific concept which may yet yield, with attentive field study, some taxonomically useful infraspecific units. Pittier, who was the first to discover the true generic affiliation of four species of Inga described by Bentham, maintained only two of them, rufescens and tubulifera. He failed to mention specific differences and referred them erroneously to Pithecolobium sect. Caulanthon, that is to say to the modem genus Zygia. Britton and Rose (1928, in Cojoba) could distinguish Pittier's two species only by overlapping characters of leaflet number and size. These characters of the leaflets are weakly linked; for example, the population at Valle de San Antón in the province of Coclé, Panama, segregated as P. rufescens var. vallense Schery, has the few (3-4-jugate) leaflets proper, to rufescens sensu stricto but in the low size- range proper to tubulifera sensu stricto. Floral bracts measuring 1-1.5 mm, ±2 mm, and to 4 mm have been found close together, on plants with essentially identical foliage, within the confines of Barro Colorado Island. The extremes of pubescence are notable, but almost all known examples of the species, of whatever leaf-formula, have puberulent primary venation of the leaflets, and all, without exception, have leaf-buds clothed in dense brown or bronze indumentum.
The form with glabrous or nearly glabrous leaflets relatively few in number, independently described (cf. Woodson & Schery, 1950) by Bentham as Inga membranacea, by Britton as Cojoba glabra, and by Standley as Pithecolobium davidsoniae, is apparently a submontane variant found only in western Panama and Costa Rica and may deserve varietal status. A remarkable form with leaf-stalks reduced to the petiole and only one pair of leaflets to 9 cm long is represented by a collection from Chocó (A. Fernandez NY). Another from Costa Rica (N. Zamora 1203, NY) has a leaf likewise reduced to the petiole and one pair of leaflets to 11 cm long on the same branch with leaves with two pairs of leaflets. This is likewise repeated, though with smaller leafets, on Sytsma & D’Arcy 3636 (MO). Numerous collections with leaves reduced to two pairs of leaflets are known from Panama.
Cojoba whitefoordiae L. Rico was said to differ from C. rufescens in its larger leaflets, ferrugineous- hirsutulous peduncles, and persistent cymbiform floral bracts. We have found that none of these characters serve to distinguish the two taxa. Cojoba whitefoordiae was said to have leaflets 14.5-24 cm long; those of C. rufescens 5-10 cm. However, a number of specimens (e.g., D. R. Harvey 5191, F) have leaflets on flowering branchlets as short as 9.5 cm and as long as 17 cm. Other specimens identifiable as whitefoordiae on the basis of floral bracts have leaves as short as 9.5 cm. The pubescence on the peduncles of both species is basically the same and, furthermore, is as variable within rufescens sensu stricto as it is between the two. While it is true that the majority of the collections identifiable as rufescens do have linear or linear- elliptic bracts, as opposed to the spatulate bracts of whitefoordiae, some have bracts linear at the base of the capitulum becoming spatulate near the apex. Moreover, some have spatulate bracts throughout. Collections that have leaf-stalks reduced to the petiole and only one pair of leaflets occur sporadically in both taxa.
In the protologue, Cojoba undulatomarginata was compared to C. glabra (= rufescens), from which it was said to differ by the membranous leaflets with undulate margins, long, cylindric glands between the leaflet-pairs, and the long floral bracts that persist through fruiting. Undulate leaflet-margins are occasionally seen on many ill-prepared collections of Cojoba, especially those with not yet fully mature leaflets, and are especially common on collections of C. rufescens. The floral bracts are perfectly compatible with those of C. rufescens. Only the long-stalked nectaries make C. undulatomarginata different from C. rufescens (though such are also found in several other species), but as far as known these are not duplicated in any other collection of pinnate-leaved Cojoba from Costa Rica and are not sufficient difference for specific status.
San José Costa Rica Central America| Panama Central America| Chocó Colombia South America|