THE SPOROPHYTE OF SPHAGNUM SUBSECUNDUM 
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the second type in which the basal cells are regular and slender and remain 
so for some time, apparently serving as a distinct boring organ aiding the 
young sporophyte in digesting its way into the stalk of the archegonium 
(figs. 15, 18, 20, 21). Such a structure is somewhat suggestive of an in- 
verted suspensor. Figures 22 and 23, sketched from living material, give 
Fig. 18. Embryo showing 12 primary segments, the maximum number found in the 
material studied. The sporophyte is of the slender, regular type. Figs. 19 and 20. Later 
stages of development. In the embryo shown in figure 20 the foot proper will develop 
above wall x-x. Fig. 21. Basal portion of young embryo at later stage than figure 20. 
The foot proper is beginning to develop along the region h-h. All X 180. 
some idea of how quickly the young sporophyte bores its way out of the 
venter. In figure 22a, the embryo has already begun to digest the cells of 
of the venter immediately below it. In figure 22&, the embryo has worked 
its way entirely out of the venter and is embedded in the stalk of the arche- 
gonium. Figure 23 shows a still later stage in which the stalk of the arche- 
gonium has developed considerably in thickness, and illustrates the expan- 
sion of the basal portion of the young sporophyte to form the foot. It 
should be noted, however, that the immediate basal cells of the slender 
type do not form this expanded foot. In the embryo shown in figure 20, 
the foot will arise from the cells above the segment x — x. In figure 21 
the expansion to form the foot proper can be observed at & — h. 
