Glossary of plant morphology others may form a tight spiral, or whorl, around the flower stem. First, at the base, are those non-reproductive structures involved in protecting the flower when it is still a bud, the sepals, then are those parts that play a role in attracting pollinators and are typically coloured, the petals, which together with the sepals make up the perianth (perigon, perigonium). If the perianth is differentiated, the outer whorl of sepals forms the calyx, and the inner whorl of petals, the corolla. If the perianth is not differentiated into sepals and petals, they are collectively known as tepals. In some
Trichostema simulatum long cyme of flowers growing from the stem between each leaf pair. Each flower has a hairy calyx of sepals with triangular points and a tubular, lipped purple corolla. The four protruding stamens are curved. Trichostema simulatum Trichostema simulatum is a species of flowering plant in the mint family known by the common name Siskiyou bluecurls. It is native to the southern Cascade Range in northern California and southern Oregon, and in the northern Sierra Nevada in California. It grows in open and generally sandy or gravelly sites of Yellow pine forests and adjacent habitats, at in elevation. "Trichostema simulatum"