Category: T
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Thorn
Short pointed woody structure derived from a reduced branch; Often applied (wrongly) in a looser sense for any sharp structure on a branch. A stiff, woody, modified stem with a sharp point. A sharp-pointed, stiff, woody part of a plant; typically evolved from a branch (compare to “prickle” and “spine”). A pointed shoot, sometimes this…
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Thigmotaxis
Response to mechanical stimulus, either by movement (as in Mimosa pudica) or by growth (as in stems or tendrils of climbing plants). The negative or positive response of certain motile cells to touch.
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Therophyte
(In Raunkiaer’s system) plant with growing point surviving adverse season in the form of seeds.
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Theca (plural thecae)
The locules, usually two, of an anther.
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Thallus
Vegetative structure not clearly divided into stem and leaf (as in Lemna). Having a simple plant or fungus body without differentiation into leaves or leaf-like structures. A plant body not separated into a distinct stem and leaves, as in Duckweeds (Lemnaceae), and in many lower plants such as Algae, some Liverworts and Lichens, etc. A…
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Thalloid
In the form of a thallus.
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Thalamus
Receptacle; (In Compositae/Asteraceae) disc; Calyx (as in Linnaeus) [old-fashioned term]. Two egg-shaped masses of nerve tissue deep within the brain. It is an important relay station, which seems to act as a filter for sensory information flowing into the brain. The thalamus also may play a part in short- and long-term memory. A pair of…
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Textured
The way a structure feels to the touch.
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Tetrasporangiate
(Of anthers) four-celled.
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Tetrapterous
With four wings.