A systematic revision of the genus Catopsis (Bromeliaceae).

摘要

Investigation of floral development showed that dioecism in Catopsis is due to suppression of floral organs during the mid-stage of floral ontogeny. In pistillate flowers, the stamens appear completely formed in the floral meristem, but become non-functional and abortive at a later stage. Similarly, in staminate plants, the ovary becomes non-functional and abortive also at a later ontogenetic stage. In plants with perfect flowers both the pistil and the stamens are fully developed at maturity. The presence of minute, normal appearing floral organs in some herbarium collections makes it difficult to ascertain the actual sexuality of those plants, and this has intensified the taxonomic confusion within the genus. Functional dioecism is predominant in some species, but only occasional or completely absent in others.; Developmental studies of the seeds showed that the unique seed-appendage of Catopsis develops early from the apical, chalazal part of the ovule before the outer integument is formed. This pattern of development differs from that observed in other members of the Tillandsioideae (e.g., Tillandsia and Glomeropitcairnia), in which the seed appendage develops basally (i.e., at the micropylar end) as an extension of the outer integument. Both types of seed appendages are thus interpreted as non-homologous.; The unique seed appendage of Catopsis is regarded as a relatively primitive character, whereas development of dioecism is likely to be a derived condition within the subfamily Tillandsioideae. In the author's view, Catopsis represents a relatively ancient group which later evolved a dioecious reproductive system. Recent molecular studies on the chloroplast gene nhd F (Terry & Brown 1997) supports this hypotheses. Despite the uniqueness of the apical seed appendage, other characters such as superior ovary, simple leaves with entire margins, and the exclusive epiphytic habitat, as well as molecular data, link this genus to other members of the Tillandsioideae. Realignment of Catopsis into a separate subfamily is not recommended.; Seven formal taxonomic realignments after the last revision of the genus by L. B. Smith and R. J. Downs (1977) are proposed as follows: C. floribunda L. B. Smith var. occidentalis var. nov. = C. paniculata E. Morren, pro parte, not as to type. C. glauca nom. nov. = C. montana sensu L. B. Smith, pro parte, not as to type. C. micrantha L. B. Smith = C. pedicellata L. B. Smith (pistillate plant). C. nutans (Sw.) Griseb. var. wawranea comb. nov. = C. wawranea Mez. C. paniculata E. Morren s. s. = C. mexicana L. B. Smith (staminate plant). C. sessiliflora (R. et P.) Mez forma werckleana comb. nov. = C. werckleana Mez. C. wangerinii var. pisiformis comb. nov. = C. pisiformis Rauh. (Abstract shortened by UMI.)