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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.
The presence of hairs on leaves, which may be coloured differently from the leaf itself, can also produce variable coloration. This is found in various Begonia species and their hybrids. Sometimes venal variegation occurs – the veins of the leaf are picked out in white or yellow. This is due to lack of green tissue above the veins.
When and how the leaves change color depends on tree species – some have leaves that just turn brown and fall. Weather and temperature also impact fall foliage. Warm, sunny days accompanied by ...
A greater proportion of aphids that avoid apple trees with red leaves manage to grow and develop compared to those that do not. [16] A trade-off, moreover, exists between fruit size, leaf color, and aphids resistance as varieties with red leaves have smaller fruits, suggesting a cost to the production of red leaves linked to a greater need for ...
Learn why leaves change colors in fall every year. The pretty, vibrant colors that autumn brings is one of the greatest things about the season! Learn why leaves change colors in fall every year.
In most such species, the tumbleweed is in effect the entire plant apart from the root system, but in other plants, a hollow fruit or inflorescence might detach instead. [1] Xerophyte tumbleweed species occur most commonly in steppe and arid ecosystems , where frequent wind and the open environment permit rolling without prohibitive obstruction.
As the growing season progresses, keep an eye out for a white or grayish-white powder on your plants. That’s powdery mildew, a fungus that affects a wide range of fruits, vegetables and flowers ...
Marcescent leaves may be retained indefinitely and do not break off until mechanical forces (wind for instance) cause the dry and brittle petioles to snap. [9] The evolutionary reasons for marcescence are not clear, theories include: protection of leaf buds from winter desiccation, and as a delayed source of nutrients or moisture-conserving ...