220 FLOWERS AND THEIR WORK. 



sepaline and petaline parts (e.g. Tulip). Some flowers, how- 

 ever, have a perianth which is composed of a single ring or 

 series of parts only, while others have no perianth. 



The perianth forms the non-essential part of the flower, 

 whereas the stamens and carpels are the essential organs, 

 and one or both of these must be present to constitute a 

 flower. A "typical" flower possesses sepals, petals, stamens, 

 and carpels arranged in single or double alternating rings, 

 each ring containing the same number of similar parts, but 

 frequently the parts are arranged in a spiral, especially the 

 stamens. Flowers which have no carpels are said to be 

 " male " or staminate ; those without stamens are " female," 

 carpellary, or pistillate. 



251. Perianth. This term is sometimes used to include the 

 calyx and corolla together, but more often" it is applied to the flower 

 envelope when there is no distinction, or very little, in colour and 

 texture between the outer and inner parts of the envelope. For 

 instance, the perianth of Tulip and Bluebell consists of six similar 

 coloured leaves, free from each other (polyphyllous) or only slightly 

 joined at the base. In Lilies and Hyacinths the perianth is gamo- 

 pliyllous, consisting of a lower tubular part and six free lobes. In 

 Daffodil and Narcissus, besides the tube and the lobes there is a 

 collar-like outgrowth or corona at the mouth of the perianth-tube. 



Examine and sketch the perianths of the following flowers : 

 Tulip, Hyacinth, Solomon's Seal, Snowdrop, Daffodil, Narcissus 

 (several kinds, to show variation in form of corona, Fig. 87), Early 

 Purple Orchid, Bee Orchid, Twayblade Orchid, Lady's Slipper Orchid. 



252. Calyx. The primitive, or simplest, type of calyx consists of 

 spirally arranged sepals, which arise directly from the receptacle, 

 as small green sessile leaves. The individual sepals may be free 

 (polysepalous calyx), or more or less united (gamosepalous calyx). 

 However complete the union may be, the number of sepals which take 

 part in the formation of the calyx is usually indicated by the pointed 

 teeth borne on the upper margin of the tube. 



When a calyx is present, it is usually composed of two (Poppy), 

 three (Lesser Celandine), four (Wallflower), or five (Buttercup) sepals. 

 More rarely the sepals are numerous, and retain their primitive spiral 

 arrangement (Water-lilies, Cactuses). 



The calyx commonly serves to protect the flower while it is still 

 young, and hence, when the flower opens, the sepals either fall off 

 (Poppy) or turn back (Dog Rose). Another of its functions, however, 

 is to protect the developing fruit, and hence it often persists until the 

 fruit is formed, as in the Bean, Strawberry, and Dead-nettle. A 

 gamosepalous calyx affords not only a more efficient protection to the 



