| Publication Type: | Journal Article |
| Year of Publication: | 2005 |
| Authors: | Bogner, J., Goncalves E. G. |
| Journal: | Willdenowia. Mitteilungen aus dem Botanischen Garten und Museum Berlin-Dahlem. Berlin-Dahlem |
| Volume: | 35 |
| Start Page: | 333 |
| Pagination: | 344 |
| ISSN: | 0511-9618 |
| Abstract: | Two new species of Xanthosoma sect. Acontias, X. mariae and X. latestigmatum, are described and illustrated. They have pilose, pedate leaf blades as have in Xanthosoma only X. plowmanii and X. pottii, and their pollen grains are released as monads, unlike in all other Xanthosoma species, which, as far as studied, release the pollen in tetrads. X. mariae is an evergreen plant mainly distinguished by its dark green velvety lustrous leaf blades with numerous leaflets and tuber-like swellings at the junction of petiole and blade; the gynoecium is of the Acontias type and the ovary is pilose in the lower part. X. latestigmatum is seasonally dormant and has medium green leaf blades with numerous leaflets and no tuber-like swellings; the gynoecium is of the Caladium type (with a very broad stigma) and completely glabrous. The relationship of the genera Caladium and Xanthosoma is discussed, C. paradoxum is transferred to Xanthosoma and the new combination X. paradoxum validated, and a key to the genera of the tribe Caladieae given. |
| DOI: | 10.3372/wi.35.35216 |
| Full Text | Two new species of Xanthosoma Schott cultivated in recent years in the Botanischer Garten München are described here. X. mariae has been collected only once in Peru by Mary Sizemore. X. latestigmatum was at first thought to have been collected only once in Venezuela by Manfred Speckmaier; we then recognized it among other collections from Venezuela and Colombia, the earliest having been made by H. F. A. von Eggers in 1891. X. mariae is a very handsome species of horticultural value and has already been used in breeding by John Banta (Alva, Florida). However, it is somewhat sensitive in cultivation and has to be grown in Europe in deep shade with high temperature and humidity. We were very surprised to find that the pollen grains of both species are released as monads and not in tetrads as expected (see discussion in Mayo & Bogner 1988). SEM studies of more material confirmed this finding. When Mike Madison (1981) studied the Caladieae, he concluded that pollen grains are released as monads in Caladium and as tetrads in Xanthosoma. Our findings show that this does not hold true. Both new species clearly belong to X. sect. Acontias due to their possession of a tuber and pedate leaves, a combination of characters not found in Caladium. Moreover, our two new species are apparently closely related to the Brazilian species X. plowmanii Bogner (1986) and X. pottii E. G. Gonç. (Gonçalves 1999), with which they also share the remarkable character of pilose leaves. |