Abstract Detail

Systematics Section/ASPT

Talent, Nadia [1], Buck, Kathleen [2], Han, Shery [2], Dickinson, Tim [1].

An online key, a polyclave, to assist systematic work on a diploid-sexual/polyploid-agamospermous complex: Crataegus of western North America (Rosaceae).

As in many genera that feature apomictic reproduction, the infrageneric field identification of Crataegus has defeated some of the most intrepid botanists, and the resulting confusion has crept into some of the summary literature. Diploids reproduce sexually, but agamospermy in polyploids requires pollination and is facultative, so that hybridization and ploidy-level transitions are moderately frequent. The taxa include diploid species with variable morphology, uniform polyploid clones, long-established polyploids with variability, and non-established hybrids that may originate repeatedly. To minimize our own frustration with field collections and the literature, we need access to the data using initially only the most easily assessed characters, followed by refinements as insight and effort build. Approach: -The software used is the Open Delta reimplementation of Delta-Intkey, funded by the Atlas of Living Australia, http://code.google.com/p/open-delta/. -Ploidy-level and reproductive-mode data were initially indispensable. -Geography was rejected as misleading because of the need to match multiple-origin hybrids. -A literature index was incorporated as a character (with 18 states), particularly to track peripheral mentions of taxa. -Because taxon descriptions are frequently separated in the literature from their reassignments to series and sections within the genus, redirections were entered as fake taxa, e.g., “For C. williamsii see series Purpureofructi”. -Photographs from the field and herbarium are heavily used as far as they were available. Results: -In the specialist literature, typographical errors and amendments to descriptions are easily mistaken for differences of opinion, but an encouraging result is that we now interpret the taxonomic history to involve little disagreement. -The literature index proved helpful as soon as it was implemented, primarily for re-evaluating varied terms for character states. -Redirections for taxa are more numerous than the taxa themselves (56:43). -Close-up photographs of flowers and fruit taken in the field are invaluable for verifying identifications. -Removing or merging taxa, while not entirely easy in Open Delta, is frequently needed and possible.

Broader Impacts:

1 - Royal Ontario Museum, Natural History, 100 Queen's Park, Toronto, ON, M5S 2C6, Canada
2 - University of Toronto, Ecology and Evolutionary Biology

Keywords:
Systematics
agamic complex
Polyploid complex.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:30 PM
Number: PSY029
Abstract ID:792
Candidate for Awards:None