MacMillan: OBSERVATIONS ON PTERYGOPHORA. 741 
4. Tangential section through secondary cortex, showing the some- 
what fusiform outline of the cells in this section (x 50). 
5. Longitudinal section through region of Fig. 3. On the left is 
seen the tissue of the secondary cortex, in the middle the flattened 
cells of the transition zone, and on the right the cells of the primary 
cortex. This first ring of growth, caused by the superposition of 
secondary upon primary tissue, is the most prominent of all the 
‘growth rings in the stipe ( X 50). 
6. A portion of the secondary cortex tissue shown in Fig. 5, mag- 
nified to demonstrate the pits in the vertical walls of the tracheid- 
like elements. To the right the cells become compressed, passing 
into the transition zone (x 250). 
7. A portion of the primary cortex tissue shown in Fig. 5, mag- 
nified to demonstrate the different arrangement of primary and 
secondary cortical cells. The secondary stand in long rows at the 
same level. This is not true of the primary (x 250). 
8. Cross section through one of the rings shown in Fig. 1 and 
magnified to demonstrate the flattening of cells in the region of the 
ring and their denser contents. The appearance of small cells inter- 
polated between the larger ones can be understood by referring to Fig. 
4 (X 250). 
g. Cross section through pith web of stipe, showing anastomosing 
filaments and trumpet hyphe embedded in a gelatinous matrix (xX 
250). 
10. Cross section through haptere. The cells of the outer cortical 
region are crowded with contents, and do not differentiate clearly. 
Near the middle of the section are seen two of the characteristic 
growth-rings of the haptere (x 50). 
11. Longitudinal section through haptere, showing the development 
of secondary tissues, the cells of which are shorter upon the primary 
tissue towards the bottom of the figure. Below the black outer cortex 
a growth-ring in section may be seen (x 60). 
12. Section through sorus, showing floor-cells, gonidangia with 
gonidia and paraphyses capped with cuticular knobs characteristic of 
this genus and of Lessonia (x 320). 
All the figures in Plate LXIL. are from original photomicrographs 
by Mr. H. L. Lyon. 
