ISHS Acta Horticulturae 570: VIII International Symposium on Flowerbulbs
THE NEW PHYLOGENY OF THE LILIOID MONOCOTYLEDONS |
| Author: | A.W. Meerow |
| Keywords: | cladistics, geophytes, molecular systematics, monocotyledons, phylogeny |
| DOI: | 10.17660/ActaHortic.2002.570.2 |
| Abstract:
In 1969, Huber radically challenged concepts of familial and ordinal limits of the monocotyledons, emphasizing less conspicuous characters, particularly embryological characters, over gross floral or vegetative morphology. Huber’s work highlighted the heterogeneity present in many traditional monocot families, especially Liliaceae. Much of this work was refined and placed into phylogenetic context by the late Rolf Dahlgren and coworkers. In Dahlgren, Clifford, and Yeo’s 1985 synthesis, the lilioid monocotyledons are recognized as two orders, the Asparagales, (31 families) and Liliales (10 families) that have evolved many traits in parallel. Two of the most important and consistent characters separating these two orders are the presence of septal nectaries in the ovary and phytomelan in the seed coat of Asparagales. Perigonal nectaries and the absence of phytomelan characterize the Liliales. To date, phylogenetic analyses of the monocotyledons, based on both morphological and multiple gene sequences, have supported this classification with some amendment (for example, Iridaceae and Orchidaceae, classified with Liliales by Dahlgren et al. are now known to belong to Asparagales). The consequence of the phylogenetic approach to classification of the lilies has been the recognition of a sizable number of small families. Most taxonomists believe that classification which reflects true phylogeny is preferable to a synthetic taxonomy that lumps unrelated but convergent taxa into large, unnatural families. The latest research on the new synthesis of monocot evolution is reviewed, with particular emphasis on families rich in horticulturally important geophytic genera, such as Amaryllidaceae, Hyacinthaceae and Liliaceae. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
