Cave Primrose

Subdivision: Angiospermae - The Angiosperms
Class: Magnoliopsida
Subclass: Dilleniidae
Order: Primulales

Family: Primulaceae, Primrose Family. Contains 22 genera and 800 species.
Genus: Primula is a form of the Latin word primus meaning "first" - in reference to this plant's very early spring flowering. Originally primroses were called prima vera "first flower of spring." This changed to the French word primaverle which the English corrupted to primerole then pryme rolles, finally ending up at primrose.
Common name: Cave Primrose or Easterflower, refers to the growing habitat of the plant and the early spring blooming period around Easter.

Range

Southeastern Utah to northern Arizona. The type specimen was collected near Bluff, Utah.

Habitat
Many primroses grow in wet locations, and many species found on the Colorado Plateau grow in montane areas. The cave primrose is the exception, growing at lower elevation sites. They grow in moist sites in alcoves or hanging gardens, from 3,488' to 5,208' in elevation. In the hanging gardens, the plants either grow within tiny exfoliations of the overhanging wall or in the sandy accumulations at the base of the wall.

Description

Cave primroses are perennial. The leaves are 3/4-8" long, spatula-shaped to elliptical, with the margins of the leaves toothed. The leaves are two-toned, green above and mealy-white on the undersides. Often, the old withered leaves remain attached to the base of the stem.

From the basal cluster of leaves, a 2-11" long leafless, flowering stalk arises and bears a cluster of flowers, 1 to 40, at the tip. The flowers are arranged in umbels - a term that means arising from the same point, like the way the ribs of an umbrella arise from a common point. Each lavender to pink flower is borne on a short stalk. The flower's corolla has 5 2-lobed petals (they look heart-shaped) with lobes that spread flat, and are joined at their base to form a narrow tube that is longer than the calyx. Each flower is 1/2-3/4" wide. The top of the corolla tube is rimmed in white or yellow and is sometimes called the "eye" of the flower.

A small egg-shaped capsule contains many roughened seeds. The wind rattles the capsule and shakes the seeds free. The roughened texture of the seeds enables them to cling to minute soil patches or algal mats on the alcove wall, or on the sandy deposits at the bottom of the alcove wall.

The flowers may bloom early in the season, January or Februray and often finish blooming by May.

Pollination

Most primroses have a slightly offensive odor, sometimes reminiscent of skunks or carrion. This odor is not to scare away pollinators; rather, the smell attracts flying insects such as muscid flies, which resemble the common house fly, to the flower. The insects collect nectar from the base of the flower tube and are dusted with pollen on their foreheads or probosci. As they fly about to other Easterflowers, they complete the process of pollination.

Notes

Cave primrose are endemic to the Colorado Plateau, which means they are restricted mainly to Entrada or Navajo Sandstone formations (they do grow in other formations) in their geographical area.

The stamens are attached to the inside of the petals and sometimes are longer or shorter than the styles.

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