3^6 PLANT STUDIES 



within the flower, but below it (Fig. 132), and the flower 

 is often said to have an " inferior ovary." 



4. From apocarpous to syncarpous flowers. — In the 

 simpler flowers the carpels are entirely distinct, each car- 

 pel organizing a simple pistil, a single flower containing as 

 many pistils as there are carpels (Fig. 324, A). Such a 

 flower is said to be apocarpous., meaning " carpels separate." 

 There is a very strong tendency, however, for the carpels of 

 a flower to organize together and to form a single com- 

 pound pistil (Fig. 324, B^ C), such a flower being called 

 syncarpous^ meaning "carpels together." 



5. From poly pet alous to sympetalous flowers. — While the 

 petals are entirely distinct from one another in the lower 

 forms, a condition described as poly pet alous., in the highest 

 Angiosperms they are coalescent, the corolla thus becoming 

 a more or less tubular organ (Figs. 73, 74). Such flowers 

 are said to be sympetalous, meaning " petals united." 



6. From regular to irregular flowers. — In the simplest 

 flowers all the members of one set are alike, and the flower 

 is said to be regular (Fig. 74, a, h). In certain lines of 

 advance, however, there is a tendency for some of the mem- 

 bers of a single set, particularly the petal set, to become 

 unlike. For example, in the common violet one of the 

 petals develops a spur ; while in the sweet pea the petals 

 are remarkably unlike. Such flowers are said to be irregu- 

 lar (Fig. 74, c, ^, e), and as a rule irregularity is associated 

 with adaptations for insect pollination. 



These various lines appear in all stages of advancement 

 in different flowers, so that it would be impossible to deter- 

 mine the relative rank in all cases. However, if a flower is 

 naked, with indefinite numbers, hypogynous, and apocar- 

 pous, it would rank very low ; but if it has a calyx and 

 corolla, is completely cyclic, epigynous, syncarpous, sym- 

 petalous, and irregular, it would rank very high. 



243. The gametophytes. — As in the case of the Gymno- 

 sperms, the gametophytes of Angiosperms are exceedingly 



