Abstract Detail



Systematics

Whittemore, Alan [1].

A flow-cytometry survey of Hedera in North America.

The genus Hedera consists of about 12 species native to the Old World. Allopolyploidy has been important in speciation, and different species are diploid, tetraploid, hexaploid, and octoploid.  In North America, Hedera is a serious invasive, but specimens are hard to identify accurately without ploidy information.  In order to clarify the taxonomy of feral ivies in North America, a survey was made of ca 140 spontaneous plants from ± natural habitats in 22 states, plus Ontario.  Four species were found to escape from cultivation, three of which are highly invasive over large parts of the continent.  Interspecific hybridization among the invasive species was evident, both the formation of triploid plants (presumably by crossing between diploid and tetraploid taxa) and homoploid hybridization among tetraploids.


1 - UNITED STATES NATIONAL ARBORETUM, 3501 New York Ave NE, Washington, DC, 20002, United States

Keywords:
Hedera
Araliaceae
invasive plants
polyploidy.

Presentation Type: Oral Paper
Number:
Abstract ID:341
Candidate for Awards:None


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