page_title: Glossary of botanical terms
section_title: C
hierarchical_section_title: Glossary of botanical terms / C
caption_attribution_description: Français&#160;: Jeunes pousses de Zanthoxylum semés dans un gobelet en plastique&#160;; photo prise juste avant rempotage (les pivots commencent déjà à tourner en rond).
context_page_description: This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of leaf morphology.
context_section_description: C, C−, C+
  In lichenology, "C" is an abbreviation for the test result of placing 5% solution of calcium hypochlorite or sodium hypochlorite (e.g. household bleach without additives) on the cortex or medulla of a lichen, to note the change in color, with no reaction noted as "C−", and production of a bright colour noted as "C+".
  caducous
  Falling off early, e.g. the sepals of poppies, which fall off when the petals begin to open. Compare persistent and fugacious.
  caespitose
  Tufted or turf-like, e.g. the growth form of some grasses.
  calcarate
  possessing a spur.
  calcareous
  A soil type or a lichen substrate rock type that is rich in or largely composed of calcium carbonate.
  callose
  Hardened; thickened; callous.
  callus
  1.  A protruding mass of tissue.
   
  2.  Undifferentiated tissue growth formed in response to wounding; may be grown in vitro.
  3.  In orchids, fleshy outgrowths from the labellum which can be variously shaped from papillae to plates.
   
  4.  In grasses, a hardened extension from the base of a floret (formed from the rachilla joint and/or the base of the lemma) which may or may not elongate and is often covered in hairs or bristles.
  calyciflorous
  Having petals and stamens attached to the calyx.
  calycophyll
  A leaf-like structure formed from a sepal or calyx lobe which enlarges, usually many-fold, before or after anthesis, especially when most of the other sepals or calyx lobes retain their original size. More extreme than an accrescent calyx, calycophylls are found in Rubiaceae. Compare semaphyll and pterophyll.
  calyculate
  Having an epicalyx.
  calyculus
  1.  A cup-shaped structure formed from bracts resembling an outer calyx.
   
  2.  In some Asteraceae, a circle of bracts below the involucre.
  calyptra
  A hood or lid. See operculum.
  calyx
   
  A collective term for the sepals of one flower; the outer whorl of a flower, usually green. Compare corolla.
  calyx tube
  A tube formed by the fusion of the sepals (calyx), at least at the base.
  cambium
  A tissue layer that provides partially undifferentiated cells for plant growth.
  campanulate
  Bell-shaped.
  camptodromous
  Pinnate venation in which the secondary veins curve toward the margins, in some cases becoming nearly parallel with them, and not reconnecting with other veins to form loops.
  campylotropous
  When the ovule is oriented transversely (i.e. with its axis at right angles to its stalk) and with a curved embryo sac. Compare amphitropus, anatropous, and orthotropous.
  canaliculate
  Channelled; having a longitudinal groove.
  canescent
  Approaching white in color, as in a leaf covered with white down or wool.
  canopy
  The branches and foliage of a tree; the crown. Also refers to the protective upper layer of a forest. Compare trunk.
  capillary
  1.  A tube, pore or passage with a narrow, internal cross-section.
  2.  Slender; hair-like.
  capitate
  1.  (of an inflorescence) Having a knob-like head, with the flowers unstalked and aggregated into a dense cluster.
  2.  (of a stigma) Like the head of a pin.
  capitulum
  A dense cluster of sessile or subsessile flowers or florets, e.g. a flower head in the daisy family, Asteraceae. See pseudanthium.
  capsule
  A dry fruit formed from two of more united carpels and dehiscing when ripe (usually by splitting into pieces or opening at summit by teeth or pores).
  carduoid
  In the Asteraceae, having a style with a ring of sweeping hairs borne on the shaft of the style below the style branches.
  carina
  See keel.
  carinal canal
  A longitudinal cavity in the stems of Equisetum and extinct Equisetopsida, coinciding with a ridge in the stem surface.
  carneous
  Flesh-coloured, especially as applied to some flowers.
  carnose, carnous
  Fleshy or pulpy in texture, especially as applied to some tissues or organs. Contrast coriaceous and corneous.
  carpel
  The basic female reproductive organ in angiosperms, either consisting of a single sporophyll or a single locule of a compound ovary, with a style and a stigma. The gynoecium is the collective term for all of the carpels of a single flower.
  carpopodium
  On achenes (Cypselas), an elongation of the base of the gynoecium which looks distinct
caption: Cotyledons of seedlings of Koelreuteria. One plant shows the first new leaves above its cotyledons; the rest show various younger stages of emerging cotyledons.
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