Cyme

Cyme, a general name for all forms of definite or centrifugal inflorescence. In these cases the main peduncle or "podium" terminates in a flower, others being subsequently developed laterally. Cymes are either multilateral (polychasial) or unilateral. In the former case two or three branches of equal vigour spring from below the terminal flower, themselves are terminated by flowers and repeat the process, as in the stitchwort (dichasium) or the thorn-apple (trichasium). In unilateral cymes, at each bifurcation only one branch grows vigorously, so that a pseud-axis is formed by the primary axis, one of its primary branches, a secondary branch, a tertiary branch, etc. These inflorescences are, therefore, also termed sympodial. They may either be bostrychoid, where each successive branching is on the same side, as in Hemerocallis; or cicinnal, where the vigorous branch is alternately right and left of the median line, as in the sundew (Drosera) and stone-crop (Sedum acre). These cymes, however, being often difficult to explain without careful study of development, are sometimes named after indefinite inflorescences which they resemble. Thus Sedum has a spicate cyme; Campanula, a racemose cyme; the guelder-roses, corymbose cymes; and geranium, an umbellate cyme. A crowded cyme of sub-sessile flowers, as in sweet-william, is called a fascicle, or if axillary, as in the box, a glomerule, whilst two glomerules in the axils of opposite leaves, as in the dead-nettles or the purple loose-strife, are known as a verticillaster. A somewhat irregular cyme is the anthela (q.v.).