Cam02

Content

Systematics

This strongly supported clade contains 12 species of North American distribution, seven of them being annual (Githopsis diffusa, G. pulchella, G. specularioides, Heterocodon rariflorus, C. angustiflora, C. griffinii, C. exigua), and five perennial (C. aparinoides, C. californica, C. prenanthoides, C. robinsiae, and C. wilkinsiana). In our analyses, C. robinsiae–C. aparinoides form a first diverging clade, while C. exigua–C. griffinii is sister to a last clade including all remaining taxa. The petD topology is by large congruent with smaller clades obtained from combined cpDNA analyses that included either six (Haberle & al. 2009) or eight species [Wendling & al. 2011]. Our results, nonetheless, do not support the inclusion of C. scouleri in this clade [Haberle & al. 2009], (Wendling & al. 2011) a fact that could be better interpreted as a misidentification between C. scouleri and C. prenanthoides, both species having somewhat similar corollas.

Interestingly, three out of the four bell-flowers endemic to California (the rare C. sharsmithiae from the Shasta Mountains of North California is missing), all annuals, morphologically similar, and with strong affinities to serpentine soils, do not form a clade. Indeed, further cytological and palynological data also support the genetic separation between C. angustiflora (n = 15; 6-porate pollen) and the C. exigua–C. griffinii clade (n = 17; pantoporate pollen) (Morin 1980). Campanula angustiflora is embedded in an internally rather unresolved clade otherwise comprising both slender, chiefly cleistogamous, and xerophytic annuals (Githopsis and Heterocodon), along with more shade-tolerant, chasmogamous perennials (C. californica, C. prenanthoides, and C. witasekiana).

Overall, the origin of the American clade Cam02 can be inferred in the Early to Middle Oligocene (32.91 Ma [19.09–38.91]), and current lineages started to diverge in the Early Miocene (c. 20.45 Ma [11.49–25.76]). It seems premature, without rigorous biogeographic reconstruction to conclude to either a single long distance dispersal event or a more progressive series of geodispersal events from Eurasia to the Americas.


From: Mansion & al. (2012: 11)

References


Haberle R.C., Dang A., Lee T., Penaflor C., Cortes-Burns H. & al. 2009: Taxonomic and biogeographic implications of a phylogenetic analysis of the Campanulaceae based on three chloroplast genes. – Taxon 58: 715–734
.

Mansion G., Parolly G., Crowl A.A., Mavrodiev E., Cellinese N., Oanesian M., Fraunhofer K., Kamari G., Phitos D., Haberle R., Akaydin G., Ikinci N., Raus T. & Borsch T. 2012: How to Handle Speciose Clades? Mass Taxon-Sampling as a Strategy towards Illuminating the Natural History of Campanula (Campanuloideae). – PLoS ONE 7 (11).

Morin N. 1980: Systematics of the annual California Campanula (Campanulaceae). – Madroño 27: 149–163.

Wendling B.M., Galbreath K.E. & DeChaine E.G. 2011: Resolving the evolutionary history of Campanula (Campanulaceae) in Western North America. – PLoS ONE 6 (9).

Synonymy

Cam02