38(.» 



T'LANT STUDIES 



It is the combination of cliarai-ters wliicli detci-niiiics a 

 grou]). 



250. Monocotyledons. — In the MonoeotyleJons about forty 

 families are recognized, containing nnmerons genera, and 

 among these genera the twenty thousand species are dis- 

 tributed. It is evident that it will be impossible to con- 

 sider such a, vast array of forms, even the families being too 

 numerous to mention. 



Prominent among the families are the aquatic })ond- 

 weeds of various Icinds, the marsliy ground cat-tails, the 

 grasses and sedges, the tropical palms, the aroids, the lilies, 

 and the orchids. Of these, the grasses form one of the 

 largest and one of the most useful groups (if plants. It is 

 world-wide in its distribution, and is remarkable in its dis- 

 play of individuals, often growing so densely over large 

 areas as to form a close turf. If the grass-like sedges 

 be associated with them there are aliout six thousand 

 species, representing nearly one third (jf the Monocotyle- 

 dons. Here belong the various cereals, suga.i-canes, bam- 

 boos, and pasture grasses, all of them innueusely useful 

 plants. 



The palms and the aroids each number about one thou- 

 sand species, and are conspicuous members oE tropical vege- 

 tation. 



In temperate regions, however, the lilies and their allies 

 stand as the best representatives of Monoi'ntvledons, with 

 their usually conspicuous and well-organized flowers. 



In nuudjer of species the orchids form the greatest 

 family auiong the Monocotyledons, the species being vari- 

 ously estimated from six thousand to ten thousand. In 

 display of individuals, however, the orchids are iu>t to be 

 compared with the grasses, or even with the lilit's, for in 

 general they are what are called "rare plants." Orchids 

 are the most highly developed of Monocotyledons, and tlu'ir 

 Ijrillia.nt coloration and biza.n-e forms a.r(> associated with 

 marvellous ada}>tations for insert visitation. 



