V EG ETA TIVE REP ROD UCTION. 



251 



the sporangia burst, or are moist and sticky, adhering to 

 each other in larger or smaller 

 clusters (fig. 264). Sometimes, 

 as in orchids and milkweeds, they 

 are all held together in one mass 

 by the remnants of the mother 

 cells in which they were formed, 

 and are attached to a part of the 

 tissue of the anther which carries 

 the mass as a stalk or handle (figs. 

 272, 273). Dry spores are usually FlG 

 adapted to distribution by wind; 

 while the adherent spores are 

 adapted to carriage by small ani- 

 mals, especially insects. (See further ^[481.) 



352. Germination in place. — By the time the sporangia 



270. - Mature condition of the 

 stamens and carpels of fig. 269. a, 

 3 branched stamens; g, three car- 

 pels with bases united and only the 

 styles distinct. Compare with figs. 

 268, 269. Magnified about 3 diam. 

 -After Frank. 



Fig. 271. — Pollen grains. A, white water lily {Nymph&a a Hut). B, a thistle (Cirsium 

 ne morale). C, a mallow {Hibiscus ternatus). D, dandelion (.Taraxacum offi- 

 cinale). Magnified 200 diam. — After Kerner. E, pine, showing bladdery enlarge- 

 ments, b, b, of the outer layer of the cell-wall. The central portion is the body of the 

 spore filled with protoplasm with a large nucleus. From it is separated a lenticular 

 cell, /, the rudiment of the gametophyte. Magnified 400 diam. — After Strasburger. 



are old enough to release the spores, the latter have already 

 germinated and begun to form a new sexual plant, the male 

 gametophyte. Thus the spores of the non-sexual plant give 



