PROCEEDINGS SfP 2 4 1990 OF THE CALIFORNIA ACADEMY OF SCIENCES Vol. 46, No. 14, pp. 299-326, 12 figs. September 11, 1990 NEW SPECIES AND NEW COMBINATIONS IN BLAKEA AND TOPOBEA (MELASTOMATACEAE), WITH AN HISTORICAlT PERSPECTIVE ON GENERIC LIMITS IN THE TRIBE BLAKEEAE By Frank Almeda Department of Botany, California Academy of Sciences, Golden Gate Park, San Francisco, California 94118 Abstract: Blakea P. Browne and Topobea Aublet, the two currently recognized genera in the Blakeeae have been variously combined and segregated during their long history. A synoptic taxonomic history of these genera is presented with special attention given to characters used to combine or separate them. In keeping with traditional generic concepts, Blakea and Topobea are maintained and a revised generic key is provided to accommodate anomalous or unusual Mesoamerican species. Descriptions, diagnostic illustrations, discus- sions, and distribution maps are presented for four new species of Blakea (B. gregii, B. hammelii, and B. herrerae from Panama; and B. scarlatina from Costa Rica and Nicaragua) and three new species of Topobea {T. fragrantissima, T. hexandra, and T. suaveolens from Panama). The study of recently collected flowering material of B. crassifolia and B. parvifolia necessitates their transfer to Topobea and the adoption of a new name, T. caliginosa, for the narrow Panamanian endemic previously known as B. micrantha. Received February 2, 1990. Accepted March 14, 1990. The striking morphological isolation of the Introduction Blakeeae within the family and the homogeneity The largely pantropical Melastomataceae of its constituent taxa undoubtedly account for comprise some 200 genera and approximately the fact that its tribal status has not been seriously 4,800 species. This comparatively large natural challenged since it was established by Bentham family has traditionally been divided into four- and Hooker (1867). However, Blakea P. Browne teen tribes based on fruit characters, staminal and Topobea Aublet, the two currently recog- features, and seed morphology. Of the eight tribes nized genera in the tribe, have been variously restricted to the western hemisphere, only the combined and segregated during their long his- Blakeeae and Miconieae are berry-fruited. The tory. Blakeeae are readily recognized by their axillary Recent fieldwork done in connection with the flowers that are individually subtended by two preparation of a treatment of Melastomataceae pairs of decussate bracts, ovoid to pyramidal for Rora Mesoamericana has resulted in the dis- smooth seeds, and wood with multiseriate rays covery of several undescribed species in the and frequent occurrence of druses (Koek-Noor- Blakeeae. An effort to devise a rational basis for man et al. 1979; ter Welle and Koek-Noorman assigning these taxa to one genus or the other has 1981). necessitated another look at generic limits in the [299] 300 PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES, Vol. 46, No. 14 tribe. I recently expressed serious reservations figures prominently in decisions to maintain To- about the continued recognition of Topobea and pobea as a distinct genus. In choosing the epithet even suggested that it be submerged in the older parasitica, Aublet was responsible for perpetrat- and larger genus Blakea (Almeda 1989). Addi- ing a misunderstanding of the epiphytic habit tional study of this problem, coupled with the that is common to so many species of Blakea paucity of information on pollen morphology and Topobea. (Patel et al. 1 985) and chromosome numbers (Solt The younger Linnaeus (1781) and de Jussieu and Wurdack 1980), has led me to refrain from (1789) maintained Blakea and Topobea as de- merging Blakea and Topobea without a compre- fined by Aublet. By retaining Blakea quinque- hensive study throughout the extensive neotrop- nervia Aublet [=Bellucia grossularioides (L.) ical range of these genera. Triana] in Blakea, it is clear that their interpre- The following summary provides a synoptic tation was a broad one that included at least two taxonomic history of Blakea and Topobea to- genera now relegated to two different berry-fruit- gether with an assessment of the diagnostic fea- ed tribes. tures used to combine or separate them. This is David Don (1823), in an early paper devoted followed by descriptions of four new species of to the Melastomataceae, was the first to part ranks Blakea, three new species of Topobea, and three with his predecessors by merging Topobea and generic transfers. Working within the constraints Blakea. His decision, however, was based on of a geographically defined study, my decision characters other than anther morphology. The to recognize Blakea and Topobea is, of necessity, weakness of Don's argument is best conveyed by tempered by the historical consensus of opinion his own words: "Although the Topobea of Aublet among specialists in the family and the need for recedes somewhat from Blakea, in its being par- more data. Nevertheless, a slight modification of asitical; yet, notwithstanding, in the Lambertian original generic concepts is necessary to accom- Herbarium are several unpublished species, from modate the accretion of new and unusual Central Don Jose Pavon, natives of Peru, and not par- American species. asitical, which agree with Topobea in every es- sential point; and these also, accord well with Blakea, except in having four, instead of six scales, Synoptic History of surrounding the calyx, which, however, is a vari- Blakea and Topobea able character; and, therefore I think myselfjus- The genus Blakea was first defined by Patrick tified in uniting these two genera." De Candolle Browne (1756) for a Jamaican species that was (1828) also adopted this interpretation in his subsequently given the binomial B. trinervia by Prodromus. Like Don and his immediate pre- Linnaeus (1759). Browne's circumscription of decessors, de Candolle's broad generic concept Blakea included a plate and a brief diagnosis of Blakea included species now recognized in describing it as a shrub with nitid trinerved el- Bellucia. liptic leaves, 6-merous axillary flowers, and tri- Naudin (1852) rejected this inclusive dispo- angular laterally connate anthers. The plate is sition and emphasized diversity in anther mor- generalized and provides no details of anther phology and habit as reasons for resurrecting To- morphology. The terse description is sufficient, pobea. He provided no involved explanation to however, to preclude confusion with the allied justify his decision, yet he described a new genus, genus Topobea, which was described and illus- Pyxidanthus, to accommodate three new species trated by Aublet (1775) from material collected that he considered closely related to Blakea. The in French Guiana. Although many of Aublet's concept of Blakea and Topobea espoused by published drawings are mixtures and some of his Naudin was faithfully followed by Bentham and descriptions are composites of discordant ele- Hooker (1867) without comment. ments (Howard 1983), both the plate and de- Triana (1871), as astute specialist in the Me- scription of T. parasitica emphasize the oblong lastomataceae, synonymized Pyxidanthus under subulate anthers that are typical of so many Blakea along with Valdesia Ruiz and Pavon, species in this genus. Curiously, Aublet over- another minor generic segregate. Pyxidanthus, looked or chose not to describe and illustrate the Valdesia, and the subsequently described Ama- broad, gaping, dorsally inclined, confluent anther raboya Linden are now universally accepted syn- pores. This is another diagnostic character that onyms o^ Blakea. As recognized by Triana (1871), ALMEDA: NEW BLAKEA AND TOPOBEA 301 Blakea included those species with short, oval in press; Gleason 1935, 1958; Wurdack 1973, or elliptic, apically blunt or rounded anthers with 1980) and other authors of major regional treat- two minute well-separated pores. Topobea in- ments of the Melastomataceae (Standley 1924, cluded those species with linear-oblong or subu- 1938; Standley and Williams 1963), except Mac- late anthers with two confluent dorsally inclined bride (1941). Invoking a rationale similar to that pores. Baillon (1879), who was noted for his broad of Baillon, Macbride combined Blakea and To- view of generic limits, was unimpressed by these pobea and commented on the inconsistency of differences in anther morphology. He returned the filament character used as a diagnostic fea- Topobea to the synonymy o^ Blakea but provid- ture by Cogniaux. ed no convincing reasons aside from a comment In a paper describing many new species of describing the anthers of Topobea as more elon- Blakea and Topobea, Gleason (1945) sympa- gate and narrower than those in Blakea. For a thized with, but rejected, Macbride's view. The botanist who excelled in character analysis, Bail- close relationship between these two genera is Ion's brief treatment of these genera reflects a readily apparent in their many parallel and over- superficial understanding of the anther differ- lapping variations in habit, leaves, indument, ences between them. floral bracts, petals, calyx lobes, ovary cell num- The most comprehensive and perhaps most ber, and seeds. Although Baillon (1879) and inffuential accounts ofgeneric limits in the Blake- Macbride (1941) intimated that anther charac- eae are those of Cogniaux (1888, 1891). Cog- ters provide insufficient grounds on which to base niaux was undoubtedly influenced by Triana. the recognition of genera, Gleason (1945, 1947), Unlike Triana, however, he was the