Chapter 7. 
MALFORMATIONS AND INJURIES. 
Malformations arising as sports or by malnutrition. Healing 
of wounds. Injuries due to lightning, frost, etc. Harmful 
effect of smoke and fog. 
Abnormal development of various parts of plants 
whether of vegetative or of reproductive organs may be 
regarded as malformations. Many of these arise as sports 
or mutations, and may be transmitted to the progeny of 
the plant. In the case of the vegetative organs such occur- 
rences as pitcher-shaped leaves have been noted in many 
imstances. Leaves of this type are of no special advantage 
to the plant, they may indeed be a disadvantage, causing 
water to collect on the leaf surface and thus increasing the 
lability to fungal attacks. Among ferns an excessive 
development of the margin of the frond leads to the 
development of so-called crested varieties, which being 
pleasing to some tastes, have been perpetuated by artificial 
selection. We have no knowledge of the causes of such 
excessive development of the leaves, nor are we certain 
of the origin of similar unnatural developments in stems, 
such as appear in the case of “ fasciation” (from the Latin 
fascis, a bundle). ‘This term is applied to the abnormal 
development of the stem into a broad flattened structure, 
often caused by the fusion of several stems, or by the union 
of lateral shcots with the main stem. Superabundance of 
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