114 



THE STAMENS. 



[lesson 17. 



295. To discharge the pollen, the anther opens (or is dehiscent) 

 at maturity, commonly by a line along the whole 

 length of each cell, and which answers to the 

 margin of the leaf (as in Fig. 231) ; but when 

 ' the anthers are extrorse, this line is often on the 

 outer face, and when introrse, on the inner face 

 of each cell. Sometimes the anther opens only 

 by a chink, hole, or pore at the top, as in the 

 Azalea, Pyrola or False Wintergreen (Fig. 235), 

 &c. ; and sometimes a part of the face separates as a sort of trap-door 

 (or valve), hinged at the top, and opening to allow the escape of the 

 pollen, as in the Sassafras, Spice-bush, and Barberry (Fig. 236). 

 Most anthers are really four-celled when young ; 

 a slender partition running lengthwise through^ 

 each cell and dividing it into two compartments, 

 one answering to the upper, and the other to the 

 lower, layer of the green pulp of the leaf. Oc- 

 casionally the anther becomes one-celled. This 

 takes place mostly by confluence, that is, the two 

 cells running together into one, as they do 

 slightly in Pentstemon (Fig. 237) 

 and thoroughly in the Mallow Family (Fig. 238). 

 sometimes it occurs by the obliteration or disappear- 

 ance of one halt of the anther, as in the Globe Ama- 

 ranth of the gardens (Fig. 239). 



296. The way in which a stamen is supposed to be 

 constructed out of a leaf, or rather on the plan of a 

 leaf, is shown in Fig. 240, an ideal figure, the lower 

 part representing a stamen with the top of its, antler 

 cut away ; the upper, the corresponding upper part of 

 a leaf — The use of the anther is to produce 

 297. Pollen. This is the powder, or fine dust, commonly of a yel- 

 low color, which fills the cells of the anther, and is discharged during 

 blossoming, after which the stamens generally fall off or wither away. 



But 



FIG. 335, Stamon of Pyrola ; the anther opening by holes at the top. 



FIG. 236. Stamen of Barberry j the anther opening by uplined valves. 



FIG. 237. Stamen of Pentstemon pnbescens ; anther-cells slightly confluent. 



FIG. 238. Stamen of Mallow ; the two cell.s confluent into one, opening round the margin. 



FIG. 239. Anther of Globe Amaranth, of only one cell i the other cell wanting. 



FIG. 340 Diagram of the lower part of an antlier, cut across above, and the Ufiper part o( 

 a leaf, to stiow how the one answers to the other. 



