Reproduction in Flowering Plants 



211 



The two groups differ in their 

 flowers also. In the monocots the 

 nvimber of parts of the calyx and 

 corolla is usually three, and the 

 stamens and divisions of the pistil 

 are three or some multiple of three. 

 In the dicots the parts of the flower 

 are typically in fives or foiurs, or in 

 a multiple of these. 



Thus the names " mono cot " and 

 " dicot " relate to the form of the 

 embryo; but the two groups are 

 further distinguished by differences 

 in leaf venation, bimdle structure, 

 bimdle arrangement, and flower 

 plan. 



The gymnosperms and angio- 

 sperms. We have previously learned 

 that the conifers bear their seeds on 

 scale leaves arranged in cones. A 

 study of one of these cones shows 

 that the seeds are formed on the 

 upper surfaces of the scales and are 

 not inclosed in capsules. When the scales mature and be- 

 come dry, the cone opens and the seeds fall out. The word 

 " gymnosperm " means " naked seed," and this is the group 

 name for the conifers and all other plants whose seeds are 

 not inclosed. 



The angiosperms are what we usually call the flowering 

 plants, although some of them, like the grasses and forest 

 trees, do not produce flowers with colored parts. The seeds 



U. S. Dept. oj Agriculture 

 Fig. 127. Fruit of mango. 

 This much-prized fruit has 

 hitherto been grown only in 

 the tropics, but recently it has 

 been introduced into southern 

 Florida. 



