Siskiyou Lewisia

Description

A cotyledon is a significant part of the embryo within the seed of a plant, and is defined as "the embryonic leaf in seed-bearing plants, one or more of which are the first to appear from a germinating seed." The number of cotyledons present is one characteristic used by botanists to classify the flowering plants (angiosperms). Species with one cotyledon are called monocotyledonous ("monocots"). Plants with two embryonic leaves are termed dicotyledonous ("dicots"). In the case of dicot seedlings whose cotyledons are photosynthetic, the cotyledons are functionally similar to leaves. However, true leaves and cotyledons are developmentally distinct. Cotyledons are formed during embryogenesis, along with the root and shoot meristems, and are therefore present in the seed prior to germination. True leaves, however, are formed post-embryonically (i.e. after germination) from the shoot apical meristem, which is responsible for generating subsequent aerial portions of the plant. The cotyledon of grasses and many other monocotyledons is a highly modified leaf composed of a scutellum and a coleoptile. The scutellum is a tissue within the seed that is specialized to absorb stored food from the adjacent endosperm. The coleoptile is a protective cap that covers the plumule (precursor to the stem and leaves of the plant). Calandrinia are a large genus of flowering plants known as purslanes and redmaids. It includes over 100 species of annual and perennial herbs which bear colorful flowers in shades of red to purple and white. Plants of this genus are native to Australia, western South America, Central America, and western North America. Some species have been introduced to parts of New Zealand, southern Africa, Asia, and Europe. Species in the genus Calandrinia are annual or perennial herbaceous plants with a sprawling or erect habit. The leaves are mostly basal and may be either alternate or opposite in arrangement. Flowers are produced in cymes. Each flower produces between four and eleven petals, though often five. Flowers may be white, purple, pink, red, or yellow. The genus Calandrinia was erected in 1823 by German botanist Carl Sigismund Kunth. It was named for Jean Louis Calandrini (1703–1758), a Genevan botanist. The genus is classified in the family Montiaceae. It was previously placed in the purslane family, Portulacaceae.