A caryopsis is a type of achene in which the pericarp is completely fused to

A caryopsis is a type of achene in which the pericarp

This preview shows page 4 - 6 out of 12 pages.

A caryopsis is a type of achene in which the pericarp is completely fused to the seed coat; it is derived from a 2-3 carpellate, superior ovary and is found only in the grasses (family Poaceae). A cypsela is an achene similar to a caryopsis, except that it is derived from a 2-carpellate inferior ovary and often is equipped with a pappus; it is found only in the composites (family Asteraceae). A nut is hard and bony, and larger than but otherwise similar to an achene, while a nutlet is a small nut. A samara has a wing, enabling it to be wind dispersed. A utricle is similar to an achene, except that the pericarp is inflated and appears like a bladder. Dehiscent, dry fruits include: capsule, follicle, legume, loment, schizocarp, silicle , and silique . A capsule is always derived from a compound pistil and splits open at maturity along one or more lines of dehiscence. A follicle is derived from a single carpel, has one or more seeds, and splits open at maturity along the dorsal (front) line of fusion. Fruits of the Fabaceae are called legumes or loments and are derived from single carpels. A legume dehisces on both sides at maturity, while the loment breaks apart into one-seeded segments. A schizocarp splits apart at maturity into one-seeded parts (mericarps) that represent its separate carpels. Silicles and siliques are specialized capsules found only in the Brassicaceae; each of these has a membranous partition that separates the two locules and each is formed from a two-carpellate gynoecium. A silicle usually is less than two times longer than wide, while a silique usually is more than two times longer than wide. Fleshy fruits may be formed either from a simple or compound ovary and include: berry, drupe , pome , and sometimes follicle or capsule . A berry may have few or many seeds embedded in a pulpy matrix with a thin outer wall. A drupe is derived from a
Image of page 4
simple or compound ovary and has one or more seeds enclosed in a stony endocarp (the inner wall of the pericarp or ovary). A pome is formed from a compound pistil in an inferior ovary; the fleshy part of the pome is derived from the pericarp and hypanthium. Follicles, derived from single carpels, and capsules, derived from compound gynoecia, are typically dry fruits, but may be fleshy in certain genera or families. Fleshy fruits derived from several ovaries include the aggregate and multiple fruit types. In the aggregate fruit, the unicarpellate ovaries of a single flower are coherent at fruit maturity, as in blackberries and raspberries. Multiple fruits are formed by the coalescence of several flowers, as in mulberry or pineapple. Fruits may serve as the dispersal unit or they may dehisce, allowing the seeds to be dispersed. The unit of dispersal, either fruit or seed, may be transported by wind, water, or an animal. Fruit types generally are consistent within a genus and often within a family, thereby providing useful characters for plant identification.
Image of page 5
Image of page 6

You've reached the end of your free preview.

Want to read all 12 pages?

  • Fall '19
  • Plant morphology, Pollen, carpels

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture