Dickinson Lab


Crataegus systematics

Crataegus phylogeny

Work on a phylogeny of the genus has begun, using molecular as well as morphological data. The tree at the left summarizes preliminary ITS data obtained while on sabbatical leave at the University of Maine, 1999-2000 (click HERE to read a more detailed report on this work so far).

Studies of North American black-fruited hawthorns (Crataegus § Douglasii Loudon)

These distinctive hawthorns occur in northwestern North America, with a disjunct occurrence in the upper Great Lakes basin.

Crataegus suksdorfii - Photo: R. M. Love
Apomixis and Crataegus taxonomy

Taxonomic complexity in genera like Crataegus involves species concepts, population structure, and reproductive biology.

Fig. 2, Dickinson et al. (1996)
Studies on Cockspur hawthorns (Crataegus § Crus-galli Loudon)

Taxonomic complexity in genera like Crataegus is especially bound up with the occurrence of gametophytic apomixis and polyploidy.

Crataegus crus-galli - Photo:  T. A. Dickinson

For more information about the genus Crataegus, please click HERE.

For more information about current research projects, as well as links to other labs working on the genus, bibliography, history, research questions, etc. please click HERE.


| Rosaceae evolution | Crataegus systematics | Morphometrics and numerical taxonomy | Comparative morphology |

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© 1999 Botany Department, University of Toronto.

Please send your comments to tim.dickinson@utoronto.ca; last updated 10-Apr-02