178 



THE REPRODUCTIVE ORGANS 



Outside is a series of small bracts resembling a calyx 

 and known as the involucre. Within this is a series of 

 small flowers which resemble a corolla, but on careful 

 examination each is seen to consist below of a small inferior 

 ovary ; the calyx is absent ; the corolla of five petals forms 

 a narrow tube below, and spreads out above in the form 



of a white pink-tipped strap. Such 

 a strap-shaped corolla is said to be 

 ligulate. There are no stamens, but 

 the style has two branches with- 

 out hairs. These very small strap- 

 shaped flowers are called ray-florets 

 (Fig. 122, 1). The yellow disk in the 

 centre is composed of florets of a 

 very different type (2). The pistil, as 

 in the ray-florets, has an inferior 

 ovary of two carpels ; there is no 

 calyx ; the corolla is long and 

 tubular, with five teeth above. 

 Each floret has five stamens, the 

 anthers of which are united to form 

 a tube round the style. Such 

 united anthers are said to be 

 syngenesious (3). These are known 

 as disk-florets. 



If the disk-florets in the head of 

 a Daisy are examined, it will be 

 seen that the outer (lower) florets 

 are the older, and are the first to 

 open. The following stages should be looked for : (1) the 

 style is short and within the anther-tube (when ripe the 

 anthers shed their pollen into the tube and on the top 

 of the stigma, which has two lobes, the outer face of 

 each being provided with a brush of hairs) ; (2) later, the 

 style elongates, and the stigmatic brush sweeps the pollen 



OV. 



Fig. 122. Florets of 

 Daisy. 1, ligulate, fe- 

 male ray-floret; 2, tubu- 

 lar, hermaphrodite disk- 

 floret ; 3, stamens with 

 united anthers ; ov, in- 

 ferior ovary; p, corolla. 



