Abstract Detail

Systematics

Guilliams, C. Matt [1], Hasenstab-Lehman, Kristen [2].

Molecular phylogenetics, biogeography, and character evolution in the western North American genus Eriodictyon (Namaceae).

Eriodictyon (Namaceae) is a small genus of perennial herbs and shrubs endemic to western North America. The 11 species or 14 minimum-rank taxa primarily occur in the California Floristic Province, although some taxa also occur in Arizona, Nevada, and Utah. While significant morphological variation exists among members of the genus, inferring the evolutionary history of the group has historically been hampered by low levels of sequence variation. Here we build a sequence dataset using double digest Restriction Site Associated DNA sequencing (ddRADseq) and use it to examine evolutionary relationships, biogeography, and character evolution in the genus. Maximum likelihood phylogenetic analyses resulted in a well-supported topology, with only three branches supported with bootstrap values below 90. Most named taxa form reciprocally monophyletic groupings, and relationships among taxa are generally well-supported. Two main clades are recovered, one corresponding to narrowly-restricted taxa of the California Central Coast (Clade 1), and the other of the remaining members of the genus (Clade 2). Clade 1 comprises taxa that that demonstrate considerable morphological diversity, with the subclade of E. altissimum and E. capitatum having linear leaves and funnel-form corollas, and the subclade of E. traskiae and E. tomentosum having lanceolate to oblanceolate leaves and urceolate corollas. Clade 2 taxa are united in having funnel-form corollas, but display morphological diversity in leaf shape, vestiture, and glandularity, as well as in corolla color. Interestingly, the perennial herb Nama lobbii is recovered as sister to Eriodictyon Clade 2 with strong support, and ought to be treated as Eriodictyon lobbii in the future. Unfortunately, Nama rothrockii has not yet been included in our analyses, but may face a similar fate. Difficult to place in earlier studies, Turricula parryi is similarly recalcitrant in our analyses, recovered as either sister to Eriodictyon Clade 1, Eriodictyon Clade 2, or to the genus as a whole. More generally, this study demonstrates the applicability of ddRADseq to studies of potentially recently diverged taxa such as Eriodictyon. The insights gained here have helped make sense of potentially conflicting morphological patterns in the genus and revealed previously unsuspected biogeographic patterns.

1 - Santa Barbara Botanic Garden, 1212 Mission Canyon Road, Santa Barbara, CA, 93105, United States
2 - Santa Barbara Botanic Garden, Conservation and Research , 1212 Mission Canyon Rd, Santa Barbara, CA, 93105, USA

Keywords:
Eriodictyon
Namaceae
California Floristic Province
ddRADseq
endemic.

Presentation Type: Oral Paper
Session: SYSTII, Systematics II: Basal Asterids & Euasterids I
Location: Virtual/Virtual
Date: Tuesday, July 20th, 2021
Time: 1:15 PM(EDT)
Number: SYSTII004
Abstract ID:745
Candidate for Awards:None