Octoraro Creek chickweed

Cerastium arvense Linnaeus var. villosissimum Pennell, Bartonia 12: 11. 1931

Decumbent sterile shoots well developed, 5-15(-20) cm. Leaves marcescent, overlapping and obscuring stem; blade broadly lanceolate to ovate, densely villous. 2n = 72.

Flowering spring. Serpentine outcrops and barrens; 100-300 m; Md., N.J., Pa.

Variety villosissimum grows in coarse grass in seepage areas on the serpentine slopes above Octoraro Creek at Lees Bridge, Chester County, Pennsylvania. Plants of var. velutinum with normal pubescence and leaf width grow nearby on the serpentine outcrops. The pubescence, leaf, and habit characters of var. villosissimum are controlled genetically (D. J. Gustafson et al. 2003) and segregation occurs in plants grown from seeds collected at Lees Bridge. These characters are displayed in varying degrees in plants growing on the serpentien barrens and outcrops in surrounding areas of Maryland, New Jersey, and Pennsylvania.

Variety villosissimum is in the Center for Plant Conservation's National Collection of Endangered Plants.

SELECTED REFERENCE

Gustafson, D. J., G. Romano, R. E. Latham, and J. K. Morton. 2003. Amplified fragment length polymorphism analysis of genetic relationships among the serpentine barrens endemic Cerastium velutinum Rafinesque var. villosissimum Pennell (Caryophyllaceae) and closely related Cerastium species. J. Torrey Bot. Soc. 130: 218-223.