Raceme

From Wikipedia
https://en.wikipedia.org/wiki/Raceme
The inflorescence of Vanda garayi, an epiphytic orchid, is a typical raceme.

A raceme ( /rˈsm/ or /rəˈsm/) or racemoid is an unbranched, indeterminate type of inflorescence bearing pedicellate flowers (flowers having short floral stalks called pedicels) along its axis. [1] In botany, an axis means a shoot, in this case one bearing the flowers. In indeterminate inflorescence-like racemes, the oldest flowers are borne towards the base and new flowers are produced as the shoot grows, with no predetermined growth limit. [2] A plant that flowers on a showy raceme may have this reflected in its scientific name, e.g. Cimicifuga racemosa. A compound raceme, also called a panicle, has a branching main axis. [3] Examples of racemes occur on mustard (genus Brassica) and radish (genus Raphanus) plants. [3]

Spike

A spike is an unbranched, indeterminate inflorescence, similar to a raceme, but bearing sessile flowers (sessile flowers are attached directly, without stalks). [2] Examples occur on Malabar nut ( Justicia adhatoda) and chaff flowers (genus Achyranthes). [3] A spikelet can refer to a small spike, although it is primarily used to refer to the ultimate flower cluster unit in grasses ( family Poaceae) and sedges (family Cyperaceae), [2] in which case the stalk supporting the cluster becomes the pedicel. A true spikelet comprises one or more florets enclosed by two glumes (sterile bracts), with flowers and glumes arranged in two opposite rows along the spikelet. [3] Examples occur on rice (species Oryza sativa) and wheat (genus Triticum), both grasses. [3]

Catkin

An ament or catkin is very similar to a spike or raceme, "but with subtending bracts so conspicuous as to conceal the flowers until pollination, as in the pussy–willow, alder, [and] birch...". [4] These are sometimes called amentaceous plants. [4]

Spadix

A spadix is a form of spike in which the florets are densely crowded along a fleshy axis, and enclosed by one or more large, brightly–colored bracts called spathes. [3] Usually the female flowers grow at the base, and male flowers grow above. [3] They are a characteristic of the family Araceae, for example jack–in–the–pulpit (species Arisaema triphyllum) and wild calla (genus Calla). [4]

Examples

Derivation

From classical Latin racemus, cluster of grapes. [5]

See also

References

  1. ^ Walters, Dirk R.; Keil, David J. (1 January 1996). Vascular Plant Taxonomy (4th ed.). United States: Kendall/Hunt Publishing Company. p.  602. ISBN  978-0-7872-2108-9.
  2. ^ a b c Wofford, B. Eugene (1989). Guide to the Vascular Plants of the Blue Ridge. University of Georgia Press. pp. 10–15. ISBN  978-0-8203-2455-5.
  3. ^ a b c d e f g Kumar, Vinay; Bhatia, S. S. (2013). Complete Biology for Medical College Entrance Examination. McGraw Hill Education Series (3rd ed.). McGraw Hill Education (India) Private Limited. p. 218. ISBN  978-1-259-06430-2.
  4. ^ a b c Gilman, Daniel Coit., ed. (1907). The new international encyclopædia. 10. Peck, Harry Thurston; Colby, Frank Moore. New York: Dodd, Mead and Company. p. 618.
  5. ^ Oxford English Dictionary. Raceme 2. Bot. A type of inflorescence in which the flowers are arranged on short, nearly equal, lateral pedicels, at equal distances along a single elongated axis