430 BOTANY. 



In cyclic flowers tliere are most frequently four or five wlioris, viz. : 



1. Tlie Calyx, composed of (mostly) green sepals. 



3. The Corolla, composed of (mostly) colored petals. 



3. (4.) The Andi osd-um, composed of one or two vi^horls of stamens. 



4 or 5. The Oynacium, composed of carpels. 



These whorls usually contain definite numbers of organs in each ; in 

 many cases the numbers are the same for all the whorls of the flower 

 (jfSomerous flower) ; vphen the numbers are different the flower is said 

 to be heteromerous. 



The terms vehich denote these numerical relations are : monocyclic, 

 applied to a flower having only one cycle ; Mcyclic, two cycles ; tricyclic, 

 three cycles ; tetracyclic, four cycles ; penta yclic, five cycles, etc. ; 

 monomerous, applied to flowers each cycle of which contains one mem- 

 ber ; dimerous, two members ; trimerous, three members ; tetramerous, 

 four members ; pentamerous, five members. 



These relations can be briefly indicated by usiug symbols and con- 

 structing floral formulae, as follows : 



Ca6, Cos, Ans, Gns = a tetracyclic pentamerous flower ; 

 Cas, C03, Aus + 8, Gns = a pentacyclic trimerous flower. 



Most commonly the members of one whorl alternate with those of 

 the whorls next above and below ; in a few cases, however, they are 

 opposite (or superposed) to each other. These relations may be indi- 

 cated by a modification of the floral formula given above, as follows, 

 where the members are alternate -. 



Gn 



An 



An 



Co 



Ca 



B 



When they are opposite the arrangement is aa follows : 



Gn 



An 



Co 



Ca 



B 



In both these formulse the position of the parts of the flower with 

 respect to the flowering axis is indicated by the position of the bract 

 B, which is always on the anterior side, while the axis is always pos- 

 terior. 



When all the members on each whorl are equally developed, having 

 the same size and form, the flower may be vertically bisected in any 

 plane into two equal and similar halves; it is then actinomorphic- 

 (= regular, and poly symmetrical). When the members in 1 ach whorl 



