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Bacterial leaf spot caused by Pseudomonas cichorii on a hibiscus leaf. Bacterial leaf spots show as necrotic, circular or angular lesions and may have a yellowish outline or halo [7] Early symptoms of bacterial leaf spots show on older leaves and lesions appear water-soaked. [12]
Although yellowing leaves might indicate that peace lilies are stressed by their environment, peace lily leaves naturally turn yellow as they age. This type of leaf yellowing typically occurs on ...
Leaf scorch (also called leaf burn, leaf wilt, and sun scorch) is a browning of plant tissues, including leaf margins and tips, and yellowing or darkening of veins which may lead to eventual wilting and abscission of the leaf.
A Liquidambar leaf with interveinal chlorosis Lemon shrub with chlorosis. Chlorosis is typically caused when leaves do not have enough nutrients to synthesise all the chlorophyll they need. It can be brought about by a combination of factors including: a specific mineral deficiency in the soil, such as iron, [3] magnesium or zinc [4]
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.
Annual autumn leaf drop in temperate zones is caused by the abscission of the mature leaves from the growth season in response to the approach of cold winter weather. Abscission (from Latin ab- 'away' and scindere 'to cut') is the shedding of various parts of an organism , such as a plant dropping a leaf , fruit , flower , or seed .
The natural variance of leaf form has been exploited in the selection of plants for the market. Broader and lobate leaves of some Alyogyne cultivars may have been hybridized with Alyogyne huegelii. The former name of Hibiscus hakeifolia and other synonyms are still given in some sources.
The hairless leaves are alternate, 8 to 15 centimetres (3 to 6 in) long, divided into 3–5 pointed lobes (cleft) and have serrate or crenate edges. They are simple and pointed at the tip. The leaves with three lobes resemble a medieval halberd because the middle lobe is much larger than the two side lobes. The five-lobed leaves also look like ...