Articles
THE NEW PHYLOGENY OF THE LILIOID MONOCOTYLEDONS
Article number
570_2
Pages
31 – 45
Language
English
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.
Hubers 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 Yeos 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.
Hubers 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 Yeos 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.
Publication
Authors
A.W. Meerow
Keywords
cladistics, geophytes, molecular systematics, monocotyledons, phylogeny
Online Articles (63)