424 



Plant Physiology 



268. Half-shade in plant propagation. In conserva- 

 tory and greenhouse production of certain tropical plants 

 whose habitats are naturally the moist, shady woods, some 

 form of shading has commonly been practiced. It is only 

 in this manner that many delicate ferns and succulent 

 species are grown successfully. The same purpose is ef- 

 fected by the cloth-covered tents or slat-covered sheds 



FIG. 117. A coffee plantation in a Hawaiian forest. [After Van Leen- 



hoff.] 



often employed in southern climates, ostensibly to dimin- 

 ish the light, but also to insure higher humidity and to pro- 

 tect against wind and frost. As a result of such work it 

 has become apparent that partial shade may be advanta- 

 geous in many horticultural or even farm crop operations. 

 The demand for vegetable products out of season is an ad- 



