The North American Perennial Species of Claytonia

Abstract

The plant genus Claytonia was named for John Clayton, a Virginian who collected most of the plant material for Gronovius' Flora Virginica. It is largely North American with most of the species being western. Two or three additional species grow in Asia, one in South America, and one in Australia and New Zealand. Most of them are found in damp places or in water, or the high-mountain forms near snow banks. The various species range from near sea level to 14,000 ft elevation, and cover all of North America except the western part of the Mississippi Valley and northeastern Canada. I became interested in Claytonia (Springbeauties) while working on a Flora of Idaho, and have since studied the collections in the herbaria of thirty-six institutions in America and five in Europe. Plants from ten additional institutions were borrowed for study. A 35,000 mile automobile trip over North America permitted me to make mass collections at the type localities, as well as at many other places, of most of the species. Pressed and dried plants, showing as wide a variation as possible of the usual characters used in species differentiation, were collected. These are preserved in the herbarium of Idaho State University, with duplicates distributed to a number of other institutions. Living plants, corms and seeds were collected and planted at the University in the greenhouse and in the garden, to see what influence a uniform environment would have on their form. Young plants of the species with thick taproots were dug, with the soil intact, and placed in paper milk cartons from which the tops had been cut. These were brought to the school, the bottoms of the cartons removed, then planted in six-inch clay pots. The seeds and corms of each'collection were kept in a refrigerator until fall; then some of each were planted in clay pots and placed in the greenhouse. Other pots were partially buried in soil in the garden. Some seeds and corms were put in a freezer and kept at 12?C for different lengths of time, while some were placed in solutions of various concentrations, and for different lengths of time, of gibberellic acid to stimulate early growth. However, the treatments had little noticeable effects, for the major factor seemed to be time for the normal rest period to pass. The results of the growth studies will be treated in the discussion of the various taxa.