Inflorescence

Inflorescence, a special region of the plant among seed-bearing plants, which bears the flowers

-and has a special method of branching of its own.

It generally also bears special leaves, besides those within the flower, which are known as bracts (q.v.). If these are absent, as in the Cruciferac (q.v.), the inflorescence is termed ebraeteate. The branch or axis bearing a whole inflorescence is termed a peduncle, which may be unbranched, as in the tulip. If branched, its branches are known as secondary or tertiary peduncles, etc.; but the ultimate branches that terminate in the flowers are called pedicels. An inflorescence rising direct from an underground stem with few or no leaves upon it is termed a scape (q.v.), as in the tulip, hyacinth, or Primula.

Inflorescences of more than one flower are divided into three classes, according to the order in which their flower-buds develop - viz., racemose or indefinite, eymose or definite, and mixed. [Branching.] In the first class the lower or outer flowers open first; the terminal bud last. In the second class the terminal bud or centre flower opens first. In a mixed inflorescence one order of branching is racemose in its development and another eymose e.g. the primary branches of one type, the secondary ones of the other. If the peduncle only bears one order of branches, the inflorescence is termed simple; if more than one, compound. Compound inflorescences may be homogeneous, if their secondary system of branching is precisely like the primary e.g. a spike of spikes or an umbel of umbels; or heterogeneous, when, though belonging to the same main class (and therefore not "mixed"), the two systems are unlike - e.g. an umbel of spikes. Racemose inflorescences may have their main axis or peduncle either elongated or arrested, and in either case the individual flowers may be sessile or stalked (pedicellate). This gives us four main types - the spilte (q.v.), with elongated axis and sessile flowers; the raceme (q.v.), with elongated axis and pedicellate flowers; the capitulum (q.v.) or "head," with an abbreviated peduncle and sessile flowers ; and the umbel (q.v.), with abbreviated peduncle but pedicellate flowers. Nearly all definite inflorescences are termed cymes (q.v.), and most of the chief modifications of the inflorescence, such as the catkin, spadix, corymb, and panicle, in addition to those already mentioned, are separately described. Mixed inflorescences are more complex. That of the horse-chestnut is a raceme ofcicinal cymes, the primary branching being racemose, the secondary cicinal. In many Labiata3 we have a spilte of verticillasters; in chicory, a bostrychoid cyme of capitula; and in Cineraria, a corymbose cyme of capitula.