136 Principles of Plant Culture. 
erally preferable to one that continuously breaks the force 
of all the rays, as does paper or whitewashed glass. 
237. Cauliflower Heads should be Sheltered from 
Sunlight to prevent the formation of chlorophyll in their 
cells, which darkens their color, and gives them a strong 
flavor. The leaves surrounding the head may be tied about 
it, or broken over so as to shade the head from the direct 
sunlight. 
B— Tue Puant As AFFECTED BY INSUFFICIENT LIGHT 
238. Insufficient Light is a Very Frequent Cause 
of Abnormal Development in plants. Some of its more 
conspicuous effects are 
a— Excessive elongation of the cells of the internodes, 
causing the plants to “draw up” or grow spindling. 
b— Deficient formation of chlorophyll (58), giving the 
foliage a pale-green, yellowish or whitish tint, and result- 
ing in 
c — Lessened assimilation, causing reduced leaf develop- 
ment and deficient vascular bundles (68). 
d— Reduced transpiration tending to watery, weak-celled 
growth. 
e — Weakening of the color and flavor of some fruits, as 
the apple and strawberry. 
Owing to these causes, plants grown in deficient light have 
tall, slender and weak stems, few and small leaves and 
scanty roots. Such plants, though of species that normally 
grow upright, are often unable to stand erect without sup- 
port. Familiar examples are cabbage and tomato plants 
that lop over when planted out, because grown in the seed- 
box to transplanting size without “ pricking off” (106); and 
