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Prickles on a blackberry branch. In plant morphology, thorns, spines, and prickles, and in general spinose structures (sometimes called spinose teeth or spinose apical processes), are hard, rigid extensions or modifications of leaves, roots, stems, or buds with sharp, stiff ends, and generally serve the same function: physically defending plants against herbivory.
Viburnum lesquereuxii leaf with insect damage; Dakota Sandstone (Cretaceous) of Ellsworth County, Kansas. Scale bar is 10 mm. Knowledge of herbivory in geological time comes from three sources: fossilized plants, which may preserve evidence of defense (such as spines) or herbivory-related damage; the observation of plant debris in fossilised animal feces; and the structure of herbivore mouthparts.
The trunk, showing the bark, leaf scars, and spines. Bark: Light brown, divided into rounded, broken ridges. Branchlets are one-half to two-thirds of an inch in diameter. The branchlets are armed with stout, straight or curved, scattered prickles and almost completely encircled by narrow leaf scars. At first light yellow brown, shining and dotted.
Prickles and thorns are an evolved defense against herbivores — animals that eat plants — and can also aid in growth, plant competition and water retention, according to the study. It was ...
Dry, one-seeded indehiscent fruit [11] in which the true fruit is not the so-called "berry", but the achenes, which are the so-called "seeds" on the infructescence, e.g. in the genus Fragaria. acicular Slender or needle-shaped. [11] See also Leaf shape. acropetal Moving from roots to leaves, e.g. of molecular signals in plants. acrophyll
The spines are the relatively large, radiating organs; the glochids are the fine prickles in the centres of the bunches. Glochids (Opuntia microdasys monstrose) Glochids or glochidia (sg.: "glochidium") are hair-like spines or short prickles, generally barbed, found on the areoles of cacti in the sub-family Opuntioideae.
For example, the article says that spines are derived from leaves, but none of the four sources I listed at User:Peter coxhead/Work page#Spines vs. thorns restrict the term to leaf-derived structures. Also, the use of spinosus as an epithet is relevant; many plants with such names have what the article calls "thorns", e.g. Prunus spinosa.
Besides their chemical content, the spiny leaves may also cause mechanical damage to the body. Iris sibirica: Siberian iris, Siberian flag Iridaceae: Most parts of the plant are poisonous (rhizome and leaves), if mistakenly ingested can cause stomach pains and vomiting. Also handling the plant may cause a skin irritation or an allergic reaction ...