CHAPTER IV 



THE PERIGONE 



Study of the Perigone.— The perigone is to be studied as to the number 

 of its circles, their color, texture, and surface, the number of parts 

 forming each, their adhesion or cohesion, if existing, the form and 

 divisions, if any, of each and of its parts, appendages, secretions, meta- 

 morphosis or other variations, arrangement of the parts in the bud, 

 movements or other noteworthy habits, and duration. 



Number of Parts. — The normal condition of two circles, the modifica- 

 tion of these through abortion, suppression, duplication and meta- 

 morphosis, and their agreement with the numerical plan of the flower 

 and its modification through the same influences, need no further 

 discussion. The number of parts entering into either perigone circle, 

 whether these exist in a distinct or coherent state, is indicated by the 

 appropriate numeral preceding the suffix "phyllous;" thus Monophyl- 

 lous, Diphyllous, Triphyllous, and so on. 



Color and Texture. — The typical idea of a calyx more or less herba- 

 ceous and a corolla thin, delicate, and brightly colored, is not always 

 realized. In the Crocus and most related flowers the parts of both 

 circles are similarly petaloid. The petals of Garcinia are thick and 

 fleshy, in Caopia they are leathery, and in Alzatea hard and almost 

 woody, at least when dry. The surfaces of the sepals, particularly the 

 outer, are not commonly glabrous, while those of the petals are; but 

 even the latter are often glandular, pubescent, densely woolly, or even 

 prickly. No shade of color is denied to either circle of the perigone, 

 nor is the color necessarily uniform among its parts or even over the 

 surface of any one part. The shade and marldngs are very liable to 

 vary in different individuals of the same species, so that color is not 

 always a good character on which to base a determination. In general, 

 the color deepens as the altitude of the habitat increases. 



Form of Parts. — The strictly typical state calls for a general resem- 

 blance between the form of the perigone parts and that of the foliage 

 leaves of the plant which bears them. They sometimes display a keel 

 corresponding to the mid-rib of the leaf, and as in the leaf, this may 



