BYRSONIMA H. B. K., Nov. Gen. Sp. 5 [quarto]: 147. 1822 [“1821”].—Lectotype, designated by Small, 1910: B. spicata (Cav.) DC.

Alcoceratothrix Nied., Arbeiten Bot. Inst. Königl. Lyceums Hosianum Braunsberg 1: 45. 1901.—Lectotype, designated by W. R. Anderson, 2007: A. rugosa (Benth.) Nied. [B. stipulacea Adr. Juss.].

Trees, shrubs, or subshrubs; vegetative hairs mostly medifixed, basifixed or stellate in a few species; stipules intra- and epipetiolar, the members of a pair distinct or partially to completely connate, persistent in most species, deciduous in a few; leaves eglandular. Inflorescence terminal, mostly a pseudoraceme of 1-flowered non-decussate cincinni but in some species a raceme of few-flowered cincinni, these sometimes reduced to a cluster of 2–3 flowers in the axil of a single bract; floriferous bract and bracteoles deciduous or persistent, eglandular, the bracteoles borne at the peduncle-pedicel joint; pedicel sessile or, in relatively few species, raised on a short peduncle. Sepals leaving outermost petal exposed in enlarging bud, all biglandular or all eglandular, the glands borne mostly below free part of sepals; corolla bilaterally symmetrical; petals light or medium yellow, white, pink, or red, glabrous in most species, the lateral 4 with slender recurved claws, the anterior pair with deeply cupshaped limbs, the posterior pair shallower, the posterior petal with a stout, erect claw and the limb smaller, flat or crumpled and often reflexed; lateral petals entire, undulate, or erose; androecium radially symmetrical; stamens 10, all fertile; filaments distinct or connate at base, alike, usually bearing some hairs at base, at least adaxially; anthers ± alike, of different lengths in some species, glabrous or hairy, the connective equalling the locules or exceeding them, with small to large glandular extensions; pollen radially symmetrical, 3-colporate; receptacle bearing straight basifixed hairs between androecium and gynoecium; gynoecium at least apparently radially symmetrical; ovary with the 3 carpels completely connate, 3-locular, all fertile or the anterior locule empty in some species; styles 3, slender and subulate with minute, apical or slightly internal stigmas. Fruit a drupe, the thin flesh green turning yellow, orange, red, purple, blue, or blue-black at maturity, the stone with a hard wall, trilocular. Chromosome number: n = 12 (W. R. Anderson, 1993a).

A genus of about 135 described species but surely larger, all American from southern Mexico, southeastern Florida, and the Caribbean to southeastern Brazil; most of the species are South American [map]. Some of these plants grow in wet forests, but the genus is most diverse in savannas and other relatively open types of vegetation. Byrsonima crassifolia sens. lat., a small tree, is a dominant species in savanna woodlands of Mexico and Central America. — Regional key to genera: USA, Caribbean, Central America.

This is the only large byrsonimoid genus, and the second-largest genus in the family. Like other byrsonimoids, these are non-vines, with intrapetiolar stipules, tricolporate pollen, and slender subulate styles with minute stigmas. Like Blepharandra and Diacidia, its closest relatives, Byrsonima has eglandular leaves, bracts, and bracteoles, carpels completely connate in the ovary, and an indehiscent fruit with a hard stone, but Byrsonima has added to the fruit a fleshy exocarp that makes it attractive to birds and is almost certainly the reason for its success in terms of numbers of species, wide distribution, and ecological diversity.

Niedenzu used the name Alcoceratothrix for B. stipulacea Adr. Juss., which has stellate vegetative hairs and deciduous stipules. The problem with using those two character-states as the basis for recognizing a genus is that they are not consistent in all the members of the B. stipulacea complex. See the discussions on pp. 22 and 25 of W. R. Anderson, 1995.

References: There is no modern revision of the whole genus; W. R. Anderson (1981b, pp. 72–137 [Byrsonima only: pdf; entire paper 20 MB: pdf], and 2001a, pp. 106–127) treated about a third of the known species.

Etymology: The name Byrsonima was first mentioned in print by A. L. de Jussieu (1811, p. 481), who ascribed it to L. C. Richard; Jussieu said the group was given that name "parce que ces espèces sont employées dans leur pays natal pour tanner les cuirs." Don (1831, p. 636) gave this explanation of the meaning of the name: "(from byrsa, a hide, and nimius, much used; because the bark of some of the species is used in tanning in Brazil)." The problem with this explanation is that bursa is Greek while nimius is Latin; it seems unlikely that Richard would have created a generic name by mixing Greek and Latin words. Besides, nimius does not mean much used; it simply means much or excessive. An alternative explanation has been proposed by Prof. Michael Shaw of Kansas University (pers. comm. via Caleb Morse). He points out that burs alone can mean leather, suggesting that -onima comes from the Greek word onymia (name), meaning "named for leather."

Uses: The fruits of B. crassifolia (L.) H. B. K. sens. lat., which are yellow and about the size of a cherry, are gathered from wild and cultivated trees from Mexico to central South America and sold in markets under the names chaparro, chaparro manteco, muricí, murucí, nance, nanche, and nancite. The fruits are eaten as is or used to make ice cream (Belém) or wine (Costa Rica), and in the Yucatan Peninsula of Mexico they are sold preserved in a sweet syrup. The astringent qualities of the bark, for which the genus was named (see above), are no longer important in tanning leather, but one does occasionally see a comment on a plant label that the bark is a febrifuge. The species B. lucida (Mill.) DC., which is native in the West Indies, Bahamas, and southern Florida, is cultivated as an ornamental shrub; it is often called locustberry.

Photos: view all: B. aerugo, B. affinis, B. altissima, B. basiloba, B. chrysophylla, B. crassifolia, B. densa, B. homeieri, B. japurensis, B. krukoffii, B. ligustrifolia, B. lucida, B. parviflora, B. pinetorum, B. psilandra, B. punctulata, B. spicata, B. stipulacea, B. verbascifolia, B. viminifolia

Drawings: view all; (those most representative of the genus in boldface): B. affinis, B. alvimii, B. bahiana, B. bronweniana, B. bucidifolia, B. cacaophila, B. carraoana, B. christianeae, B. coniophylla, B. crassifolia, B. flexipes, B. fonsecae, B. hatschbachii, B. homeieri, B. kariniana, B. lucida, B. macrostachya, B. maguirei, B. morii, B. onishiana, B. pachypoda, B. riparia, B. rodriguesii, B. rubrobracteata, B. schunkei, B. souzae, B. spinensis, B. steyermarkii, B. surinamensis, B. tillettii, B. trinitensis, B. wurdackii

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