Hieracium caespitosum and Hieracium piloselloides (Asteraceae) in the Black Hills National Forest: New state records for South Dakota, U.S.A

Abstract

Hieracium spp. (Asteraceae) are noted for their taxonomic complexity, frequent incidence of apomixis and polyploidy, and invasive tendencies. Here we report the Eurasian taxa, Hieracium caespitosum Dumort. and Hieracium piloselloides Vill., as recent additions to the flora of South Dakota. Plants were collected at three locations in the Black Hills during 2014 and 2015 and compared to specimens of H. caespitosum and H. piloselloides at major herbaria (RM, MO, SDC) for five morphometric traits. We found significant differences (P<0.05) between previously identified specimens of these species for involucre and pappus lengths and stellate leaf hair number; the latter was especially discriminatory in univariate and multivariate analyses and probably the most useful trait for field identification. Hieracium specimens from the Black Hills exhibited morphological characteristics of H. caespitosum and H. piloselloides, suggesting that both species were introduced in the region. These data will assist South Dakota land managers in identification of nascent weedy Hieracium populations and may also be of interest to biologists studying demographic and genetic factors related to weed establishment.

Citation

Dickerson, Brian E.; Mayer, Cheryl; Ramsey, Justin; Mergen, Zach; Gabel, Mark. 2016. Hieracium caespitosum and Hieracium piloselloides (Asteraceae) in the Black Hills National Forest: New state records for South Dakota, U.S.A. Journal of the Botanical Research Institute of Texas. 10(2): 541-546.