70 PART I. — ORGANOGRAPHY. 



but in some flowers they have the color of petals or some lively 

 hue other than green, in which case they are described as petal- 

 oid. The latter are illustrated in the sepals of the Larkspur, 

 Columbine and showy Lady's-slipper. When the petals are 

 distinct from each other or ununited, the calyx is described as 

 chorisepalous, or, less correctly, as polysepalous, and when they 

 are united either partially or wholly, it is called gamosepalous. 

 In a gamosepalous calyx where the union of sepals is incom- 

 plete, the united portion is called the tube, while the free or 

 ununited portion is termed the limb, and the orifice of the tube 

 is called the throat. 



In flowers belonging to the natural order Composite, the 

 calyx has its tube united to the ovary, while its limb is produced 

 into a hairy, scaly or spiny crown called a pappus. The down, 

 by means of which the ripe fruits of the Dandelion, Thistle and 

 Lettuce are wafted on the wind, is an illustration. In the Vale- 

 rian and Teasel families, the calyx-limb forms a pappus in a 

 similar manner. 



In form, the calyx may be regular or irregular : regular, 

 if its parts are evenly developed ; irregular, if some of the sepals 

 are larger or different in shape from others ; or in the case of a 

 gamosepalous calyx, if either the tube is unequal-sided or the 

 divisions of the limb are of unequal size or shape. Among the 

 more commonly occurring forms of the gamosepalous calyx are 

 the tubular or tube-shaped, the rotate or wheel-shaped, the cam- 

 panulate or bell-shaped, the hypocrateriforin or salver-shaped, the 

 urceolate or urn-shaped, and the bi-labiate, forms which corre- 

 spond to those of the corolla, presently to be described. 



The calyx very commonly remains after the corolla and 

 stamens have withered, and sometimes endures even until the 

 ripening of the fruit; in either case it is said to be persistent. 

 Not infrequently, however, it falls away at the same time with 

 the corolla and stamens, when it is described as deciduous. More 

 rarely it falls off when the flower begins to open ; in this case 

 it is described as caducous ; the Poppy and May-apple afford 

 examples. 



The calyx often becomes more or less adherent to the ovary 

 or base of the pistil, and it is a matter of much importance in 

 the study of flowers to observe whether such adhesion has taken 



