SECT. II 



PHANEROGAMIA 



487 



the ktter is said to be inferior while the flower is described as 

 EPIGYNOUS (Fig. 438, 3). 



The regions of the axis, or of other parts of the flower which 

 excrete a sugary solution to attract the pollinating animal visitors, 

 are called nectaries. Their biological importance is considerable. 



Fig. 437. — Hypogynous flower of Eanunmhis sceleratus, with numerous superior ovaries born 

 upon a club-shaped receptacle. (After Baillon, magnified.) 



In a typical angiospermic flower the organs are thus arranged in 

 five alternating whorls, of which two comprise the perianth, two the 

 androecium, while the gynaeceum consists of one whorl. The flower 

 is PENTACYCLIC. The number of members is either the same in each 

 whorl (e.g. three in a typical Monocotyledon flower, or five in a typical 

 Dicotyledon flower), or an increase or decrease in the number takes 



Fig. 438. — Different flowers belonging to the family Rosaceae, cut through longitudinally. 1, 

 Poteutilla pahistris, hypogynous ; 2, AlchemiUa alpiiia, perigynous ; 3, Pyru3 Malus, epigynous. 

 (After FocKE in Nut. I'Jhinzcii-fdmllien, magnified.) 



place. This is especially the case with the whorls composing the 

 androecium and gynaeceum. 



Some of the more frequent deviations from the floral structure described above 

 may be referred to here. Variation in the number of whorls is common. A 

 diminution in the number may result from the absence of one kind of sexual organ 

 in diclinous flowers [e.g. Myristica), or from the absence of one of the two whorls 

 composing the androecium or perianth (Compositae). Flowers in which the 

 androecium consists of only one whorl are termed haplostemonous, those with 

 two whorls of stamens diplostemonous. On the other hand, the number of whorls 



