A New Species of Aptandra (Olacaceae) from Amazonian Peru Alwyn H. Gentry and Rosa Ortiz Missouri Botanical Garden, P.O. Box 299, St. Louis, Missouri 63166, U.S.A.ABSTRACT. A new species of Olacaceae from Am-azonian Peru is described as Aptandra caudata.Aptandra caudata A. Gentry & Ortiz, sp. nov. TYPE: Peru. Loreto: Provincia Maynas, Que-brada Sucusari, N bank of Rio Napo below Mazan, mature upland forest on lateritic soil, elev. 130 m, 3�15'S, 72055'W, 7 July 1983 (fl), Gentry, I asquez & Jaramillo 42718 (ho-lotype, MO; isotypes, AMAZ, USM). Figure 1. Arbor parva, ramulis teretibus, glabris. Folia angusteelliptica vel elliptico-oblonga, apice abrupte per 1.5-3.5cm caudata, glabra, membranacea. Inflorescentia pauci-flora, pedicellis filiformibus, 1-1.5 mm longis. Flores inalabastro cylindrici, ca. 5 mm longi; calyce obtuse 4-lobulatos, 0.5 mm longo. Fructus globosus, ca. 2.5 cmidiametro, calyce subpatelliformi expanso subtensus. Treelet 3-5 m tall; branchlets slender, subterete,smooth, glabrous. Leaves narrowly elliptic or elliptic-oblong, the apex abruptly caudate-acuminate for1.5-3.5 cm, the base � cuneate, membranaceous,olive green when dry, glabrous, 3.5-15 cm long(excluding drip tip), 1.2-4.5 cm wide, the lateralnerves 6-14 pairs; petiole slender, 4-8 mm long,ca. 1 mm thick. Inflorescence an open axillary pan-icle, few-flowered, the branches slender, the pedun-cle ca. 1 cm long, the flowers arranged in 2-3-flowered umbels at ends of the inflorescence branch-es, the filiform pedicels ca. 1-1.5 cm long. Flowerbud a cylindrical tube with globose apex; calyx shal-lowly and obtusely 4-lobed, ca. 5 mm long at an-thesis, much enlarged in fruit; petals 4, linear below,somewhat broadened at apex, greenish cream, ca.5 x 1 mm, forming a strictly cylindrical tube witha globose apex; stamens 4, the filaments connateinto 4-mm-long tube, the anthers ca. 0.5 mm long,fused to an annulus, opening by a thin reflexingvalve; pistil ca. 4 mm long, the slender style apicallythickened at level of anthers. Fruit globose, single-seeded, green, ca. 2.5 cm diam., the fruiting calyxcoriaceous, becoming broadly cup-shaped to almostpatelliform, enveloping less than the basal quarterof drupe; seed globose, ca. 7 mm across. Distribution. Known only from the type locality at the Explornapo Camp on the Rio Sucusari in Loreto Department, Peru, 116-130 m elevation. Additional collections examined. PrEiR. I.ort:iTr: (allfrom type locality), 5 July 1983 (fl), Gentry et al. 42628(AMAZ, MO, USM), 14 June 1986 (st), Gentry et al.54321 (AMAZ, MO), 7 Oct. 1986 (st), Vasquez & Jar-amillo 8156 (AMAZ, MO), 7 Nov. 1989 (fr), I ~squez& Jaramillo 13103 (AMAZ, MO, USM). Only three species of Aptandra were recognizedby Sleumer (1984), two in the Neotropics and onein tropical Africa. Of these, A. caudata is closestto A. tubicina (Poeppig) Benth. ex Miers, whichalso occurs in Amazonian Peru, on account of themembranaceous, cuneate leaves and strictly cylin-dric pre-anthesis corolla tube. The most strikingdifferentiating feature of A. caudata is the con-spicuously caudate leaf apex, especially pronouncedin small leaves where a 3-cm-long leaf can have a1.5-cm-long drip tip. In contrast, .. tubicina isacuminate with the drip tip 0.5 1.5 cm long. Theleaves of A. caudata are also narrower and moreelliptic than in A. tubicina; although the latter some-times has some leaves as narrow as those of A.caudata, the narrower leaves are mostly lanceolate.The flower of A. caudata is also noticeably longer(5 mm vs. 3 mm) than that of A. tubicina and hasa more prominently globose bud apex and moreshallowly and obtusely lobed calyx. Another differ-ence is the almost patelliform fruiting calyx of A.caudata, which covers only the extreme base of thedrupe and is very different from the broadly cupularcalyx of A. tubicina, which covers most of the lowerhalf of the drupe. It is possible that two species are included in Sleumer's (1984) concept of A. tubicina: one with membranaceous to chartaceous, strongly acuminate leaves, which includes the type; the other with more subcoriaceous, subacuminate leaves and smaller, more numerous flowers, which is much more com-mon, at least in Amazonian Peru. Aptandra cau-data is vegetatively more similar to the Brazilian type material of A. tubicina than to the rest of the Peruvian material. However, A. caudata cannot be conspecific with either variant of A. tubicina be-cause of the differences in size and shape of flowers and buds and the patelliform fruiting calyx. Aptandra caudata is the largest-flowered species in the genus and approaches Chaunochiton in flower size and in the almost patelliformly expanded fruiting NOvoN 2: 153-154. 1992.