HYPOGYNOUS MONOCOTYLEDONS 



201 



and distinct from them. In such cases the ovary is said 

 to be free, or superior, and the other organs inferior, or 

 hypogynous, a word meaning "inserted under the pistil." 

 These terms should be remembered, as the distinction is 

 an important one in plant evolution. 



290. The Flower Bud. Observe the manner in which 

 the sepals and petals overlap in a partly unfolded bud. 

 Draw a diagram rep- 

 resenting their posi- 

 tion, as in Figures 

 385-387- Compare 

 this with your dia- 

 grams of leaves and 



leaf buds ; does it 

 agree with 

 them, and 



385-387. Diagrams of three modes of aestiva- 



agree with any of tion common among monocotyledons: 385, val- 

 vate ; 386, imbricate (GRAY) ; 387, convolute 

 S0 ' (GRAY). 



which ? Are the 



parts imbricated or valvate ? (Sees. 250, 256, 257.) 



The arrangement of the parts of the flower in the bud 

 is called (estivation, or prefloration, words meaning respec- 

 tively " summer condition " and " condition before flower- 

 ing." It corresponds to the vernation of leaf buds, and 

 the same terms are used in describing it. 



291. Summary of Observations. In the flower just ex- 

 amined we found that there were four sets of floral organs 

 present sepals, petals, stamens, and pistil ; that the indi- 

 vidual organs in each set were alike in size and shape ; 

 that there were the same number, or multiples of the same 

 number of parts in each set, and that all the parts of each 

 set were entirely separate and disconnected the one from 

 the other, and from those of the other cycles. Such a 

 flower is said to be : 



Perfect, that is, provided with both kinds of organs 

 essential to the production of seed stamens, and pistil. 



Complete, having all the kinds of organs that a flower 

 can have ; viz. : two sets of essential organs, and two sets 

 of floral envelopes. 



