Taxonomic changes in Ixonanthaceae from the Venezuelan Guayana

Cyrillopsis micrantha (Steyermark) P. E. Berry & N. Ramfrez is a new combination based on Ochthocosmus micranthus Steyermark and constitutes only the second known species of Cyrillopsis (Ixonanthaceae). The number of varieties in Ochthocosmus roraimae Bentham is reduced from three to two, and Ochthocosmus parvifolius Hallier f. is treated as a species of uncertain status, with no known extant type material. The family Ixonanthaceae, which is sometimes treated as a subfamily of the Linaceae, includes two genera in the Neotropics, Cyrillopsis and Ochthocosmus. These two genera are distinguished mainly by fruit and pedicel characters. Ochthocosmus has a 5-locular ovary, the fruit is a prismatically cylindric, elongate, 5-valved capsule, and the seeds have a conspicuous, thin, lateral wing. Furthermore, the pedicels are non-articulated, that is, they abscise flush with the rachis. In contrast, Cyrillopsis has a 2-locular ovary, its fruit is an elongate, slightly asymmetrical, 2-valved capsule, and the seeds lack wings but are partly covered at the upper end by a 2-lobed membranaceous aril; its pedicels are articulated, with an abscission zone and bracteoles located roughly one-third of the way up the pedicel from the rachis. Until now, Cyrillopsis was considered to have a single species, C. paraensis Kuhlman, and Ochthocosmus to have eight recognized neotropical species (Steyermark & Luteyn, 1980; Steyermark, 1984, 1988). Although some botanists, such as Mabberley (1990), consider Ochthocosmus to include species both in South America and in Africa, Forman (1965) presented convincing arguments to place the African species in the genus Phyllocosmus Klotzsch, thus leaving Ochthocosmus as a strictly neotropical group. While preparing the treatment of the Ixonanthaceae for the Flora of the Venezuelan Guayana, we examined recently collected fruiting material of Ochthocosmus micranthus Steyermark, a species that was described from flowering specimens only (Steyermark, 1988). The articulated pedicels, arillate seeds, and 2-locular fruits of these new collections place the species clearly in Cyrillopsis rather than in Ochthocosmus. The transfer of 0. micranthus to Cyrillopsis brings the number of currently recognized species in Cyrillopsis to two and in Ochthocosmus to seven. We also reduce the number of varieties in 0. roraimae from three to two by removing O. roraimae Bentham var. parvifolius (Hallier f.) Steyermark & Luteyn as a variety of this species. Cyrillopsis micrantha (Steyermark) P. E. Berry & N. Ramfrez, comb. nov. Basionym: Ochthocosmus micranthus Steyermark, Ann. Missouri Bot. Gard. 75: 318. 1988. TYPE: Venezuela. Bolfvar: Ayavaparti, 10 km SW of Wadacapiapu6, 5?18'N, 60?58'W, 1100 m, 13 Nov. 1986, Herndndez 348 (holotype, VEN; isotype, NY). [Steyermark (1988) was incorrect in citing the holotype at MO; rather, the holotype is at VEN and is so labeled, and there is no type material at MO.] Figure 1. Steyermark described this species based on two flowering specimens that strongly resemble other species of Ochthocosmus from the Guayana region. Three more recent collections from the type locality, however, Huber 11958, Huber & Herndndez 11948, and Herndndez 395, all have nearly mature fruits, and they conform to the characteristics of Cyrillopsis described above (see Fig. 1). Also, the type collection and the other specimens cited below all have the characteristic articulated pedicels of Cyrillopsis that do not occur in Ochthocosmus. This second species of Cyrillopsis has much smaller leaves than the previously known species, C. paraensis Kuhlman. Whereas C. paraensis is priNovoN 5: 227-229. 1995. This content downloaded from 157.55.39.104 on Sat, 18 Jun 2016 06:42:07 UTC All use subject to http://about.jstor.org/terms