The Flora of Panama Sapotaceae treatment by Blackwell is updated. Pouteria congestifolia Pilz and P. leptopedicellata Pilz are newly described and the combination Pouteria buenaventurensis (Aubr.) Pilz is made. As now revised, the Panamanian flora includes 44 species in 11 genera, an increase from the 24 species in 6 genera known to Blackwell. This revision is based on collections made in the past decade. Trees or shrubs with milky latex. Leaves alternate, rarely opposite; nodes mostly trilacunar, the traces evident on the leaf scar; blades simple, entire; pubescence of 2-armed hairs, one arm sometimes obsolete. Flowers solitary or clustered in axils or at recently defoliated nodes, rarely cauliflorous, perfect, rarely unisexual, actinomorphic; sepals in one or two whorls, rarely spiral, free or rarely united; corolla gamopetalous, the lobes simple or divided, usually as many as sepals; stamens generally as many as the corolla lobes and opposite them, the staminodes sometimes present between the corolla lobes, variously developed; pistil syncarpous, the style simple, sometimes obscurely lobed at the summit, the ovary superior, 1-14-loculed, the carpels uniovulate. Fruit a berry; exocarp usually fleshy, often becoming sclerotic; seeds 1-several, the testa hard, smooth, often shiny, the attachment area (scar) lateral or basal, variously developed, often rough and duller in color, the endosperm either copious on either side of the flat foliaceous cotyledons, or scanty, or absent with thick fleshy cotyledons. Scarcely 12 years have elapsed since Blackwell (1968) published the treatment of Sapotaceae for the Flora of Panama. Blackwell treated 24 species in 6 genera, while the present study treats 44 species in 11 genera. Recent collections, particularly from moist forest areas, have significantly increased the number of taxa known 'from Panama, and they have also permited the first descriptions of flowers and/or fruits for several species. Still, all too many species have inadequate series of specimens, and collectors can greatly assist future monographers by seeking flowers and fruits of all but the most common cultivated species. Determination of geographical distribution and morphological variation of most species awaits further collection of specimens. Collectors can also make valuable contributions by preserving viable seeds and/or developing flowers for cytological study. Sapotaceae are almost completely unknown cytologically, particularly American species. Patterns seen in a few chromosome counts that have been made of Old World taxa look interesting, and a more complete record might prove valuable in determining the natural affinities of certain species. 1 Assisted by National Science Foundation Grant DEB 77-04300 (W. G. D'Arcy, principal investigator). This work was initiated while the author held a National Endowment for the Arts Postdoctoral Curatorial Traineeship at the Missouri Botanical Garden. Their financial support and encouragement is gratefully acknowledged. 2 The Polytechnic, Department of Biology, Ibadan, Nigeria. ANN. MISSOURI BOT. GARD. 68: 172-203. 1981. 0026-6493/8 1/0172-0203/$3 .35/0 This content downloaded from 207.46.13.127 on Wed, 12 Oct 2016 04:30:12 UTC All use subject to http://about.jstor.org/terms 1981] PILZ-SAPOTACEAE 173 Full descriptions are included in this treatment only for those taxa not treated by Blackwell (1968). Likewise, complete lists of synonyms are not included. The nomenclature used for American Sapotaceae has been in considerable flux, and it is by no means stabilized even now. Over 200 names have been proposed for the 44 species treated in this study. Nearly half of the later synonyms are nomenclatural, reflecting the widely different concept of genera held by various authorities. More complete lists of synonyms may be found in papers cited after the generic descriptions. As a taxonomic result of this study I am describing two new species of Pouteria and transferring Richardella buenaventurensis to Pouteria.