Mosiera (Myrtaceae) in Mexico and Mesoamerica Leslie R. LandrumDepartment of Botany, Arizona State University, Tempe, Arizona 85283-1601, U.S.A.ABSTRACT. The history and relationships of themainly Caribbean genus Mosiera are discussed, andit is comprehensively described. Two Mexican andMesoamerican species, Psidinum contrerrsii and I'.ehrenbergii, are transferred to Mlosiera. Generic limits among the American Myrtinae(Myrtaceae) have long been obscure. Historicallythe greatest problem has been definition of the limitsof 'sidium I,., a large, diverse, and poorly definedgroup to which many species of Myrtinae (e.g., P.contrerasii Lundell and P. ehrenbergii (Berg) Bur-ret) have been assigned for want of a better place.Recently, Landrum & Sharp (1989) have describedand illustrated seed coat characters that can becorrelated with floral characters to separate Psidiumfrom related genera, but the above two species areamong a few that must be relocated. Psidiurm con-trerasii and P. ehrenhergii are here assigned tolMosiera, a genus that mainly has been ignored sinceits description by Small (1933).HISTORY OF MOSIEHR Small (1933) created Mosiera to contain twospecies from southern Florida that he had earlier(1913) recognized as belonging to Anarnmomis Gri-seb. (= Myrcianthes Berg). I agree with McVaugh(1973) that Small's original two species are bestconsidered as one. Small assigned both Anarmorisand Mosiera to the tribe Eugeniinae, where onlythe first genus belongs. Small recognized the speciesof Mlosiera he had before him as being distinct fromA-namromis because of characteristics of the fruitand inflorescence. Apparently unknown to him wasthe striking difference in embryo structure, the char-acter of primary importance in differentiating sub-tribes of Myrteae. Burret (1941), in his worldwide revision of MIvr-tis I. and segregate genera, considered Mosiera tobe a synonym of MVrtus. Burret's concept of Myrtusincluded the Mediterranean type, M. cormmrunis L,.,a north African species, and a complex of Caribbeanspecies, including the two that Small had originallyplaced in Mosiera. McVaugh (1968) considered the Caribbean com-plex that Burret had placed in Myrtus to be moreclosely related to American genera (e.g., CalY-colpusNOVON 2: 26-29. 1992.Berg) than 1lMyrtus, but he did not then transferthem to Mosiera or any other American genus,considering that a more thorough knowledge wasrequired before a final position could be assigned.Later (1973), he transferred the type species ofMosiera (M. longipes (Berg) Small) to Psidium. In a posthumous publication, Bisse (1985) trans-ferred several Cuban species of Myrtus, in the senseof Burret, and some species of Psidium to Mosiera.His inclusion of Psidium guineense Sw. in Miosieraleads me to believe that his concept of the genuswas quite different from mine. I consider Psidiumguineense to be a typical species of Psidium and,in fact, a close relative of P. guajava L., the type. A revision of Mosiera is underway, but I believethat it is important that Psidium contrerasii and P.ehrenhergii be transferred now so that the correctnames can be used in other publications and to bringattention to a genus until now unknown in Mexicoand Central America. Mosiera is here for the firsttime critically compared to other genera and com-prehensively described.Mosiera Small, Man. S. E. Fl., 936. 1933. LEC-TOTYPE: Mosiera longipes (Berg) Small (= Eugenia longipes Berg) selected by McVaugh (1956). Shrubs or trees to 15 m high. Hairs whitish,yellowish, or reddish brown, unicellular, simple, toca. 0.5 mm long. Leaves persistent, coriaceous, thevenation brochidodromous, with few to ca. 10 pairsof lateral veins that are united by a marginal veinthat arcs between them near the leaf margin. Inflo-rescence a solitary axillary flower (infrequently a 3-flowered dichasium) or an axillary bracteate shootwith 1-3 decussate pairs of flowers. Flowers tetram-erous; calyx lobes oblong to hemiorbicular, the calyxusually not fused or only slightly fused beyond theovary's summit, tearing slightly or not at all betweenthe lobes at anthesis; petals submembranous, white;bracteoles usually small, ovate-triangular, foliose inone species, caducous at about or before anthesis;stamens 60-200, folded toward the center in thebud; anthers globose, 0.3 0.7 mm long, usually withone terminal gland in the connective; ovary 2-loc-ular; ovules 3-40 per locule, the placenta not prom-inent, the locules sometimes connected by an open-
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