Abstract Detail

Systematics Section/ASPT

Theiss, Kathryn E [1], Kephart, Susan R [2], Archibald, Jenny K [3].

Species boundary quandaries in Hastingsia (Agavoideae, Asparagaceae).

The taxonomy of rush lilies of Southwestern Oregon and Northern California (Hastingsia; Agavoideae, Asparagaceae) has had a convoluted path. Originally merged within Schoenolirion, Hastingsia has been recognized as distinct since 1879. This generic distinction has been upheld by both morphological and genetic data; however, confusion still exists as to species boundaries within Hastingsia. The original two species, H. alba and H. bracteosa, are easily differentiated by the formation of a corolla “tube” in H. bracteosa compared to the open tepals of H. alba. Subsequently, a segregate species was described from each. Hastingsia serpentinicola was separated from H. alba based on its overall smaller stature. The segregate occurs on serpentine soils primarily in the Klamath Mountains and North Coast Ranges. This overlaps with the range of H. alba, although the latter also extends to serpentine soils further south in the Sierra Nevada mountains. Hastingsia atropurpurea was distinguished from H. bracteosa based on tepal color, slightly larger stature, and minimal range overlap. However, field analyses have since demonstrated both a large range overlap, including multiple sympatric sites, and that intermediate hybrid morphologies occur in areas of sympatry.
Recent phylogenetic analyses do not support a four-taxon hypothesis, demonstrating the need for integrating historical work with recent field morphometric study and new molecular analyses. Here we present morphological data that further support the two-taxon hypothesis. Morphological analyses of floral and fruiting characters show more variability in H. alba than in its segregate H. serpentinicola. Individuals of H. serpentinicola are generally smaller with less inflorescence branching than those of H. alba, but the overall morphological differences between the two proposed species are minimal. Similarly, there is almost complete overlap in morphological measures between H. atropurpurea and H. bracteosa. The main difference between these two taxa is floral color, with H. atropupurea having dark purple tepals whereas those of H. bracteosa are white. These data lead us to propose that H. serpentinicola be subsumed into H. alba and that H. atropurpurea be listed as a subspecies of H. bracteosa. Hastingsia bracteosa is listed as a Species of Concern by the US Fish and Wildlife and is Threatened in Oregon. Resolving the taxonomic boundaries between these taxa is important in future conservation planning.

1 - Willamette University, 900 State Street, Salem, OR, 97301, USA
2 - WILLAMETTE UNIVERSITY, Department Of Biology, SALEM, OR, 97301, USA
3 - University Of Kansas, RL McGregor Herbarium & Bridwell Botanical Research Lab, 2045 Constant Ave, Lawrence, KS, 66047-3729, USA

Keywords:
Asparagaceae
Agavoideae
Hastingsia
morphometrics
Serpentine
species delimitation
taxonomy.

Presentation Type: Oral Paper:Papers for Sections
Session: 31
Location: Pines South/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 2:45 PM
Number: 31006
Abstract ID:609
Candidate for Awards:None