136 MARGARET C. FERGUSON 



Larix are often oblique. Only one such instance has been 

 observed in Pinus and is shown in fig. 261, plate XXIII. 



Considerable variation has been noted in the origin of the 

 archegonia, a few of the irregularities, which are in fact typical 

 of all, have been figured. Figs. 262, a and b, represent two 

 sections through the upper part of the same prothallium. They 

 show twenty-three young archegonia in various stages of devel- 

 opment. Only a single archegonium of those shown in the 

 illustrations had its origin in a superficial cell ; some of them 

 originated in the sheath-cells of normal archegonia found 

 in other sections, but this fact is not demonstrated in the 

 sketches; however, in fig. 265, taken from another prothal- 

 lium, a little archegonium is seen budding, as it were, from 

 a sheath-cell of the larger archegonium, and in fig. 266 

 is shown a somewhat similar case except that here one arche- 

 gonium is directly above the other. 1 One would consider 

 it very doubtful if such an archegonium as this lower one 

 would develop further; but fig. 267 shows an archegonium 

 similarly located in which the central cell has divided, and both 

 the ventral canal-cell and the egg-nucleus are still clearly visi- 

 ble, though the latter shows some signs of disintegration. In 

 all these archegonia no neck cells have been formed. 



In one instance, nine archegonia were found Pinus in montana 

 uncinata, so arranged along the top and side of the prothallium 

 as to suggest a cock's comb seven of the archegonia being 

 apparent in a single section. The figure was reconstructed 

 from several sections in the series and the archegonia overlap 

 not all lying in the same plane, but they are all plump and 

 normal though some show early stages in disintegration. The 

 two at the top have well developed proembryos, but none of 

 the others have been fertilized (fig. 260). Archegonia are fre- 

 quently found arranged vertically as in fig. 261. In such cases 

 as this the lower ones do not arise from the one just above, but 

 each is connected with the exterior by means of a funnel-shaped 

 opening leading from its neck-cells to the side of the prothal- 

 lium ; this cannot be shown in a sketch as it is not evidenced in 

 any one section, and can only be determined by carefully 

 studying the whole series. 



1 See note at close of Appendix. 



