High mountain origin, phylogenetics, evolution, and niche conservatism of arctic lineages in the hemiparasitic genus Pedicularis (Orobanchaceae)

Abstract

The origin of the arctic flora covering the northernmost treeless areas is still poorly understood. Arctic plants may have evolved in situ or immigrated from the adjacent ecosystems. Frequently arctic species have disjunctive distributions between the Arctic and high mountain systems of the temperate zone. This pattern may result from long distance dispersal or from glacial plant migrations and extinctions of intermediate populations. The hemiparasitic genus Pedicularis is represented in the Arctic by c. 28 taxa and ranks among the six most species-rich vascular plant genera of this region. In this study, we test the hypothesis that these lineages evolved from predecessors occurring in northern temperate mountain ranges, many of which are current centers of diversity for the genus. We generated a nuclear ribosomal and chloroplast DNA phylogeny including almost all of the arctic taxa and nearly half of the genus as a whole. The arctic taxa of Pedicularis evolved 12-14 times independently and are mostly nested in lineages that otherwise occur in the high mountains of Eurasia and North America. It appears that only three arctic lineages arose from the present-day center of diversity of the genus, in the Hengduan Mountains and Himalayas. Two lineages are probably of lowland origin. Arctic taxa of Pedicularis show considerable niche conservatism with respect to soil moisture and grow predominantly in moist to wet soils. The studied characteristics of ecology, morphology, and chromosome numbers of arctic Pedicularis show a heterogeneous pattern of evolution. The directions of morphological changes among the arctic lineages show opposing trends. Arctic taxa are chiefly diploid, the few tetraploid chromosome numbers of the genus were recorded only for arctic taxa. Five arctic Pedicularis are annuals or biennials, life forms otherwise rare in the Arctic. Other genera of the Orobanchaceae consist also of an elevated number of short-lived species, thus hemiparasitism may favor this life form in the Arctic. a b s t r a c tThe origin of the arctic flora covering the northernmost treeless areas is still poorly understood. Arctic plants may have evolved in situ or immigrated from the adjacent ecosystems. Frequently arctic species have disjunctive distributions between the Arctic and high mountain systems of the temperate zone. This pattern may result from long distance dispersal or from glacial plant migrations and extinctions of intermediate populations. The hemiparasitic genus Pedicularis is represented in the Arctic by c. 28 taxa and ranks among the six most species-rich vascular plant genera of this region. In this study, we test the hypothesis that these lineages evolved from predecessors occurring in northern temperate mountain ranges, many of which are current centers of diversity for the genus. We generated a nuclear ribosomal and chloroplast DNA phylogeny including almost all of the arctic taxa and nearly half of the genus as a whole. The arctic taxa of Pedicularis evolved 12-14 times independently and are ...

Floral nectary morphology and evolution inPedicularis(Orobanchaceae)

“…long-tubed/ beaked) from generalized ancestors (i.e. short-tubed/ beakless) (Ree, 2005;Eaton et al, 2012;Tkach et al, 2014). This notion has been further supported by (Li, 1951).…”

“…long‐tubed/beaked) from generalized ancestors (i.e. short‐tubed/beakless) (Ree, ; Eaton et al ., ; Tkach et al ., ). This notion has been further supported by pollination/floral biology studies in Pedicularis , which have found that only short‐tubed, beakless species produce nectar to reward pollinators (e.g.…”

Long-Distance Dispersal after the Last Glacial Maximum (LGM) Led to the Disjunctive Distribution of Pedicularis kansuensis (Orobanchaceae) between the Qinghai-Tibetan Plateau and Tianshan Region

“…annual/biennial, insect-pollinated, outcrossing, mid-successional) and has an almost matching distribution range on the QTP with northernmost occurrences in either the Tianshan or the Altay Mts. [43,72,73], the haplotype diversity was slightly higher in P . kansuensis ( H T = 0.882 vs .…”

The spatial structure of phylogenetic and functional diversity in the United States and Canada: An example using the sedge family (Cyperaceae)

“…S5A-S5C), with particular shifts associated with occurrence in high latitudes. Adaptation to the arctic biome appears to be a recent phenomenon in many plant lineages (Abbott & Brochmann, 2003;Liu et al, 2014), and the lineages that inhabit these areas tend to exhibit phylogenetic niche conservatism (Hawkins et al, 2013;Gebauer et al, 2014;Tkach et al, 2014). Nevertheless, a large number of sedge lineages have acquired the necessary adaptations to survive in Arctic climates, including at least 48 different Carex clades (Hoffmann et al, 2017) and the genera Eriophorum and Trichophorum.…”