ORGANS OF REPRODUCTION. 291 



Fig. 629. Fig. 630. Fig. 631. 



Fig. 629. Pistil of Iris. o. Ovary, sty. Petaloid 



styles. s<ij?. Stigmas Fig. 630 Upper part 



of the style and stigma of Leschenaultia formosa. 



t. Style, s. Stigma, i. Indusium Fig. 631. 



Upper part of the style, t, of a Composite Plant 

 dividing into two branches, which are covered 

 above by collecting hairs, pc. s. True stigma. 



collecting hairs. The collecting hairs on the style of the Cam- 

 panula {figs. 117 and 118) are retractile; they have been already 

 described under the head of hairs. (See p. 49.) In the Com- 

 positae, the surface of the style is more or less covered with stiff 

 collecting hairs (^^r. 631, /»c), and as this organ is developed 

 later than the stamens, it is at first shorter than they are, but as 

 growth proceeds, it breaks through the adhering anthers, and 

 thus the hairs on its surface come in contact Avith the pollen and 

 become covered with it. In allied orders to the Compositae, 

 namely, the Goodeniacese {fig. 630, e) and the Lobeliacese, the 

 hairs form a little ring below the stigma, to which the term of 

 indusium has been given. 



3. The Stigma. — The stigma has been already described as 

 being connected with the placenta by means of the conducting 

 tissue of the style; hence it may be considered as a portion 

 of the placenta prolonged upwards, but differing from it in 

 not bearing ovules. If this be the proper view of the struc- 

 ture of the stigma, this part like the placenta must be regarded 

 as double, one half being formed by each margin of the carpel- 

 lary leaf, and hence each simple pistil or carpel has neces- 

 sarily two stigmas, the normal positions of which are lateral. 

 That eminent botanist Dr. Eobert Brown, alludes to this subject 

 in the following manner :— " That the stigma is always lateral 

 may be inferred from its being obviously so in many cases; and 

 in one genus at least, Tasmannia, it extends nearly the whole 

 length of the ovarium, so as to be commensurate with and 

 placed exactly opposite to the internal polvspermous placenta. 

 u2 



