CRYPTOGAMS AND PHANEROGAMS. 



237 



a small " placenta," similar to the one possessed by the Ferns, 

 and open towards the inside by a longitudinal cleft (Fig. 241, 

 compare Fig. 213). A section of the Coniferce agree more closely 



FIG. 212.- Stamens of Araucaria (pcllin- FIG. 243. Male flower of Taxus. 



sacs long and pendulous). 



with the Equisetaceae, in having a few (three to eight) pollen- 

 sacs arranged on the under-side of more or less shield-like leaves 

 (Figs. 242, 243, compare with Fig. 224 a, c, d). In the Abietaceos 

 the number of sporangia is diminished to two, which are placed 

 also on the lower side (Fig. 267) of a stamen. The number of 

 pollen-sacs (microsporangia) in the Angiosperms is nearly always 

 four to each stamen ; they are longitudinal projections which are 



f 



C b 



FIG. 2ii. A Cross section through a quadrilocular anther in different stages of develop- 

 ment : s the searn where it bursts open ; vf vascular bundle ; fc connective. B A stamen. 

 C Another stamen seen from the front (/) and from the back (6). 



placed in pairs on each side of the central line of the stamen, two 

 on the edge, and the other two generally on the side which is 

 turned inwards ; the pollen-sacs generally dehisce longitudinally 



