Growth and Development of Polemonium Foliosissimum on High Elevation Rangeland in Utah

Abstract

Polemonium foliosissimum A. Gray var. alpinum (Brand) is a perennial forb of high elevation aspen and herbland range. In northern Utah, the annual life cycle is completed within approximately 3 months after snowmelt; stem elongation occurs in June, flowering in July, and seed maturation and dispersal in August. A low temperature stratification treatment to the perennial parts was necessary for the initiation of stem elongation, and subsequent long photoperiods were required for continued growth and flowering. Seed germination was restricted by the copious sheath of mucilage that surrounds wetted seeds; this restriction was largely removed by a 15-min acid scarification treatment. Carbohydrate reserves in the caudex generally increased continuously from the flowering through the seed dispersal stages. Clipping treatments applied for 4 consecutive years at three phenological stages reduced subsequent growth and vigor. Recovery from clipping treatments was slow over an additional 3 years. INTRODUCTION Polemonium foliosissimum A. Gray var. alpinum (Brand), white polemonium, is an important perennial forb of high elevation aspen and herbland range, because of its abundance in localized areas and its palatability to livestock and big game. The species occurs in subalpine areas of the Intermountain States from Idaho to New Mexico and in Colorado. Davidson (1950) considered the species to be a complex of intergrading populations. Using morphological, cytological and chromatographic analyses as his basis, Anway (1968) segregated four varieties (alpinum, flavum, foliosissimum and molte) that overlap in many characters and form continuously varying populations for nearly all characters. Plants of the present study generally agreed in morphology with the characters of variety alpinum, which ranges through the mountains of northern Utah, northeastern Nevada and southwestern Wyoming. STUDY SITEES Studies were conducted in aspen and herbland range on the Mud Creek Sheep Allotment (Uinta National Forest) and Tony Grove Canyon (Cache National Forest), both in northern Utah. The environmental conditions and plant community composition are typical of high elevation sites in this region. Mud Creek was described by Matthews and Conrad (1968) and Tony Grove by Florez (1971). Polemonium is widely distributed, but plant densities are generally low in the study areas; cover values ranged from less than 1 % in aspen 1 The authors were stationed at Logan, Utah, at the Forestry Sciences Laboratory, which is maintained in cooperation with Utah State University,