150 



PARTICULAR FORMS OF FLOWERS 



ovary) are borne at the base of the spadix, and the staminate 

 flowers (each of a few anthers) are above them. The ovaries 

 ripen into red berries. In the skunk cabbage all the flowers 

 are perfect and have four sepals. The common calla of 

 greenhouses is a good example of this type of inflorescence. 

 303. Compositous Flowers. The head (anthodium) or 

 so-called, "flower" of sunflower and whiteweed and daisy 

 (Figs. 188, 189, 200), thistle, aster (Fig. 252), dandelion, 

 daisy, chrysanthemum, goldenrod, is composed of several 

 or many little flowers, or florets. These florets are inclosed 

 in a more or less dense and usually 

 green involucre. In the thistle (Fig. 

 253) this involucre is prickly. A longi- 

 tudinal section (Fig. 254) discloses the 

 florets, all attached at 

 bottom to a common 

 torus, and densely 

 packed in the involucre. 

 The pink tips of these 

 florets constitute the 

 showy part of the head. 

 304. Each floret of 

 the thistle (Fig. 255) is a 

 complete flower. At a is the ovary. At b is a much-divided 

 plumy calyx, known as the pappus. The corolla is long- 

 tubed, rising above the pappus, and is enlarged and 

 5-lobed at the top, c. The style projects at e. The five 

 anthers are united about the style in a ring at d. Such 

 anthers are said to be syngenesious. 



305. These are the various parts of the florets of the Com- 

 positae, sometimes known as the Sunflower family. In some 

 cases the pappus is in the form of barbs, bristles or scales, 

 and sometimes it is wanting. The pappus, as we shall see 

 later, assists in distributing the seed. Often the florets are 

 not all alike. The corolla of those in the outer circles may be 



257, 258. Double dahlias. In one, the florets 

 have developed flat rays. In the other, the 

 florets appear as inrolled tubes. 



