340 PLANT CULTURE 



some cause many of the seeds produce plants which are entirely 

 white instead of green; these die when a few weeks old. 



YUCCA (Adam's Needle). The hardy species of this genus 

 are all ornamental plants thriving in situations fully exposed to the 

 sun. Almost any soil will suit them. Some of the most useful 

 species are Y. gloriosa (of which there are numerous varieties), Y. 

 recurvifolia, Y. angustijolia, Y. filamentosa and Y. flaccida. The 

 commonest species grown in the North is F. flaccida, rather than 

 F. filamentosa, has stiffer leaves and coarser, curlier threads on the 

 leaves. 



Propagation. They are increased by dividing the stems and 

 planting in a shaded spot until rooted; also, in some species, by seeds, 

 and from root cuttings. 



