• PRELIMINARY REVISION OF THE GENUS .

By HENRY Pn'IIEB.

INTRODUCTION. In the course of his work on the flora of Panama, the author has found it almost impossible to proceed in the determination of the species of Inga without attempting a revision of the whole genus. Since the pUblication of Bentham's extensive monograph, in 1875, no general study of this important group has been undertaken, al­ though many new species have been described by Micheli, Harms, Oliver, Britton, and others. It is now found that the arrangement of the species has to undergo certain slight changes, that there have been misconceptions and unjustifiable modifications in the status of many species, and that a considerable number of new types await description in the American collections at hand. Of the latter, several collected by the author and others in Panama, Central America, and Venezuela are of unusual interest. It was thought possible at first to limit the present study to a re­ vision of the Inga species in the United States National Herbarium, but while this collection is relatively rich in new material, it did not offer many opportunities for comparison and definition of old types. This led to the present extension of the investigation, which em­ braces the material contained in most of the larger American herbaria. The curators of the Gray Herbarium, the New York Botanical Garden, and the Field Museum of Natural History have most oblig­ ingly lent their extensive collections, for which grateful acknowledg­ ment is here made. The Gray Herbarium is especially rich in speci­ mens from old collectors, some of which are duplicates of types (if not the types themselves) of Schlechtendal's Mexican species, and many others the types or duplicates of types of Bentham's South American species. The John Donnell Smith Herbarium, always generously put at the disposal of botanical students, has also been freely consulted. Besides, the Director of the National Museum of Costa Rica had the kindness to lend the rich local collection of the defunct Instituto ffsico-geografico, made mainly under the direction of the writer. 173 174 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM •

.A. general synopsis of the Central American species has been pre­ pared for fnture publication, but descriptions of all new species will be published in the present series, together with othe .. observations which may prove useful to the next monographer of Inga and its close ally, Pithecolobium.

SYSTEMATIC TREA TJ(ENT.

Section 1. LEl'TINGA.

NEW SPECIES.

Inga mapiriensis PUtler, sp. nov. A smoll tree S to 4 meters high; brnDchlets slender, glabrous. Leaves entlrely glabrous; petioles marginate or subalote. 0.7 to 1.3 em. long; sUpules subulnte. glabrous, about 4 mID. long, early deciduous; leal1ets I-jugate. subsesslle, cortaceous; glands very small, globose, pertuse; leaflet blades oblong­ lanceolote to Innceolnte, long-attenuate at the base, long-acuminate at the apex, the costa prominent above, the lower faee delicately reticulate. the costa hardly prominent. the whole leaflet 7 to 14.5 em. long, 2 to 4.5 em. broad. Inflorescences glabrous, ruther few- (about 10 to 20-) flowered. single In the axlls of the leaves or subpaniculate on defolInte nxlllury branchlets; peduncles 0.8 to 1.4 em. long; bractlets minute. subulate, caducous; pedlcels glabrous, 4 to 6 (5) mm. long; calyx tubular, 2.5 to 3 (2.7)1 mm. long; corolla tubular, broadenIng toward the apex, 7 to 8 (7.6) mm. long, the lo~s 1 to 2 mm. long, reflexoo. minutely glnn()ulnr,puOOscent at the tips; shUDlnal tube sllghtly ex­ ceeding the corolla. Legume not k.nown. Type In the Herbarium of the New York Botanical Garden, collected at San Carlos. neaf Maplr!, BolIvin. nt an altitude of 750 Uletp.r~, tlow(>rs, August, 1907. by Otto BuchU.n (no. 1768), Also collected between Gunoni and Tlpuool, Bolivia, April-June. 1892. Bang 1421. Closely relnted to lnga hctcrophylla nod I. pmwrclisiR, the specimens cited having b~n Identifie