THE PISTIL. 



73 



introrse anthers. In these plants the young style is much shorter than the stamens ; 

 it grows rapidly as the flower expands, and traverses the tube formed by the stamens, 

 where its hairs, rubbing the anther-cells, open them, and sweep out the pollen 

 which adheres to them; they are hence called collecting hairs or brushes (pili col- 

 lectores). In the Cornflower (fig. 430) the stigmas (Sti.) are lateral and superficial, as 

 in the Lychnis, and below them is a small swelling clothed with a tuft of very small 

 collecting hairs (pc). In the Chrysanthemum (fig. 431), the two style-branches are 

 papillose on their inner faces, and tipped by a little tuft of collecting hairs. In 

 Eupatorium (fig. 432) the two style-branches are cylindric and bristle with collecting 

 hairs ; and the stigmatic surfaces form a little band which- extends from the fork 

 half-way up the branches. In Achillea (figs. 433, 434), the heads of which are rayed, 

 the central florets are tubular and hermaphrodite (fig. 433), and the circumferential 

 are female semi-florets (fig. 434). Here the style-arms of the central florets 

 (hermaphrodite) are papillose on the inner face, and tipped with a brush of collecting 

 hairs; the semi- florets again, being female only, their style-arms (fig. 436) have 

 no collecting hairs (fig. 435), but, as the pollen of the centre florets may reach them, 

 their style-arms are papillose, so as to retain the pollen and secure fertilization. In 

 Campanula the five style-branches (fig. 437) are papillose on the inner face, and 

 subtended by five rows of collecting hairs, each row being double, and answering to 

 the two halves of each anther. Before expansion, the style grows rapidly, the 



anthers open, and their pollen- grains, which bristle 

 with hooks, adhere firmly to the hairs which have 

 swe P^ them; this accomplished, the collecting 



437. Campanula. 

 Pistil. 



439. Vine. 

 Androecium and pistil (mag.). 



438. Arum. 

 Pistil (rnag.). 



440. Elder. 

 Pistil and calyx (mag.). 



hairs are retracted within themselves, like the horns of a snail ; the pollen then 

 disappears, and the style becomes clean, its surface being merely a little rough. 



The stigma is sessile (st. sessile) when, there being no style, it is seated directly 

 on the ovary. In the Tulip (fig. 345) it forms three bi-lobed crests ; in the Nettle, 

 a pencil ; in Arum (fig. 438), a little papillose tuft; in the Vine (fig. 439), a flat- 

 tened head; in the Elder (fig. 440), three rounded lobes; in the Poppy (fig. 441), 

 velvety radiating double crests, clothing the depressed styles, which together resemble 

 a shield or cap with scalloped edges. 



The stigma is sometimes absent, and then the ovary remains open ; this is the 

 case with Pine (fig. 379), Cypress, and Thuja, the female flowers of which are arranged 

 in a spike ; each is furnished with an outer bract, which soon withers and disap- 

 pears ; each is formed of a. scale representing an open carpel, without style or stigma? 



