Advances In Monocot Systematics

Following the highly successful symposium on monocotyledons held at Kew in July 1993, much research has been generated, especially on the relationships of the asparagoid lilies.

Monocotyledons Systematics and Evolution

(eds. P.J. Rudall, P.J. Cribb, D.F. Cutler & C.J. Humphries). ISBN 0 947643 85 0. Price 45)

The proceedings of the 1993 Kew monocotyledon symposium have been published by Kew as a two-volume boxed set dedicated to the memory of Rolf Dahlgren (1932-1986). They address relationships among monocotyledons at the genus and family levels and above, with the aim of stimulating further research on higher-level monocotyledon systematics, and ultimately generating a revised classification. The taxon-based papers are interspersed with ones on character analysis, and largely use cladistic methods of analysis and character evaluation.

For details write to or email Mike Lock

Anatomy of the Iridaceae

The systematic vegetative anatomy of the iris family is described in Anatomy of the Monocotyledons Vol. 8: Iridaceae by Dr Paula Rudall, the latest volume in a series edited at Kew by Dr David Cutler and Mary Gregory. Apart from grasses, orchids, palms and aroids, Iridaceae, with some 1500 species in 86 genera, represent one of the largest monocotyledonous families and include genera of great horticultural importance (e.g. Crocus, Freesia, Gladiolus and Iris). Sword-like equitant leaves are a characteristic feature of the family, but leaf morphology is remarkably varied, particularly in cross sectional outline, ranging from zig-zag (plicate) to circular.

ISBN 019 854 504. 75. Published by Oxford University Press.

Contact: Dr Paula Rudall (0181-332 5331)

Email Paula Rudall

Current research in the molecular systematics of monocotyledons was presented by Dr Mark Chase and co-workers in a series of 13 papers at the meeting of the American Institute of Biological Sciences (5-10 August 1995). In all Mark co-authored 17 papers at the conference.

Contact: Dr Mark Chase (0181-332 5364)

Email Mark Chase

A New Family of Asparagoid Lilies

Triteleia laxa, a member of the new family growing under the Alpine Unit

A new family of asparagoid lilies based on the genus Bloomeria is to be formally published by Drs Mike Fay and Mark Chase following molecular and anatomical studies of Alliaceae (sensu Dahlgren et al. 1985). Cladistic analysis of the data revealed that Alliaceae are polyphyletic. To make the family monophyletic, Agapanthus had to be moved to Amaryllidaceae and the tribe Brodiaeeae of Alliaceae to a position close to Hyacinthaceae to form the proposed new family. There are 10 genera in the family; all are cormous plants from western North America and some are well known in horticulture (e.g. Brodiaea). Differences from Alliaceae include possession of corms rather than bulbs, hollow rather than solid styles, and three or more bracts subtending rather than two bracts enclosing the developing umbel. The onion odour is lacking from all members of the new family.

Contact: Dr Mike Fay (0181-332 5517)

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The Dasypogonoids

Thick cross sections of a leaf of Baxteria australis viewed by fluorescence microscopy. The change in fluorescence colour of the cell walls from pale blue in distilled water (above) to intense green when treated with ammonium hydroxide (below) indicates the presence of bound ferulic acid, a feature characteristic of commelinoid monocotyledons. Scale bar = 100 um.

Research in anatomy and molecular biology has indicated the taxonomic position of the Australian genera Dasypogon, Baxteria, Kingia and Calectasia (the dasypogonoids). These have been linked with both non-commelinoid and commelinoid monocotyledons, and are of obscure affinity. A critical character in monocotyledon systematics is the presence of polymer-bound ferulic acid in cell walls. Ferulic acid is present in most commelinoid monocotyledons (e.g. grasses, sedges, rushes, palms and gingers) but absent from non-commelinoid taxa (aroids, alismatids and lilioids); dasypogonoids had not been studied.

Using UV fluorescence microscopy, Dr Paula Rudall found that the cell walls of dasypogonoid genera showed the characteristic green fluorescence of bound ferulic acid when under alkaline conditions. These results and related molecular studies by Dr Mark Chase's group demonstrate that the dasypogonoids are not closely allied to asparagoid lilies, as previously thought, but to commelinoid taxa. Their affinities amongst this group are uncertain, but they may represent a hitherto undescribed order of monocotyledons, possibly related to palms.

Contact: Dr Paula Rudall (0181-332 5331)

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