Seed Germination, and Growth and Development of Rudbeckia occidentalis Nutt. (Western Coneflower) on Aspen Range in Utah

Abstract

Germination as affected by temperature and light, seed- ling growth and survival, growth and development of mature plants, and the effects of clipping on survival and regrowth of Rudbeckia occidentalis Nutt. (western coneflower) on aspen range in northern Utah were inves- tigated. The success of the species as an important component of the aspen understory and in openings is attributed to abundant production of viable seed, high germinability under a wide range of temperature condi- tions, and vigorous growth of seedlings and mature plants. coarse, perennial herb of the Compositae (Heliantheae). It is distin- guished from related species by a columnar and discoidal receptacle, nonspinescent receptacular bracts, and corollas narrowed to short tubes at the base. The roots are thick and woody, and the caudex (Fig. 2) attains a diam of 30-60 cm in older plants. In the Intermountain region, the species grows in moist to moder- ately dry, shallow soil and occurs generally from the ponderosa pine zone up to and including the spruce zone (U.S.D.A. Forest Service, 1937). It is locally abundant in many areas throughout the aspen zone in Utah. Sampson (1923) and Houston (1954) considered the species to be an indicator of fair to poor conditions on mountain range, since soil erosion and impoverishment caused by overgrazing and other abuses extended its range and abundance. The aerial parts of western coneflower are generally unpalatable to livestock; however, because of the herb's abundance and large size, it is taken occasionally by sheep late in the season when other forage is reduced. It is utilized to a minor extent by big game.