SPECIES — gea:us. 27 



48. Again, the former are distingiiislied for producing seeds 

 composed of determinate parts, as cotyledons (H25) and embryo, 

 while the latter produce certain minute bodies, (called spores, ) 

 having no such distinction of parts. Thus the Phasnogamia are 

 also called^CoTYLEDONOTjs)and the Cryi^togamiai^AcoxYLEDo- 

 Nous plants.) . 



49. Lastly, we find in the Ph8enogamia( a system of com- 

 poikid organs, such as root, stem, leaf, and flower, successively 

 developed on a determinate plan (H8-26))wliile in the Cryp- 

 togamia/ a gradual departure from tliis plan commences, and 

 they become simple expansions of cellular tissue, without sym- 

 metry or proportion.^ 



a. In the following pages we shall first direct our attention exclusively to the 

 compound organs" of Flowering Pi,ANTs"^and since, in our descriptions of these 

 organs, frequent references ■svill be made to pai-ticidar species and genera, for 

 illustrations and examples, it seems proper to subjoin, in this place, a brief notice 

 of these fundamental divisions also. 



50. 1 A Species embraces all such individuals as may have 

 originated from a common stocky Such individuals bear an es- 

 sential resemblance to each other, as well as to their common 

 parent, in all their parts. ;■ 



d. Thus the white clover, ( Trifolium repcns) is a species, embracing thousands 

 of contemporary individuals, scattered over ova- hills and plains, all of a common 

 descent, and producing other individuals of their own kind from their seed. ) The 

 innumerable multitudes of individual plants which clothe the eartli, are, so far 

 as known, comprehended in about 80,000 species. 



51. To tliis law of resemblance in plants of a common 

 origui, there are some apparent exceptions. Individuals from 

 the same parent often bear flowers differing in color, or fruit 

 differuig in flavor, or leaves differing in form. Such differences 

 are called(yAiiiETiES.\ They are never permanent, but exhibit 

 a constant tendency to revert to their original type. 



a. Varieties occur chiefly in cultivated species, as the apple, potatoe, tuL'p, 

 Geranium, &c., occasioned by the different circumstances of soil, climate, and 

 culture, to which tl'ey aitp subjected. But they continue distinct only until left to 

 multiply spontaneously rrom seed, in their own proper soil. 



52 |A Genus is an assemblage of species, with move points 

 of agi-eement than of difference, and more closely reserabhng 

 each other than they resemble any species of other gi'oupsA 



