Leavitt: OBSERVATIONS ON CALLYMENIA PHYLLOPHORA. 293 



Peculiar layers of tissue appeared in some of the older stipes. 

 These remind one of annual rings. Similar structures are 

 reported by Jonsson in such related forms as Ahnfeltia -plicata 

 and Phyllophora membranifolia. In these Jonsson found a very 

 clear layering of the cortex marked by a difference in color and 

 diameter of cells and formed probably by a division of the cells 

 of the outer cortical layer. 



The layers of stipe in Callymenia -phyllofhora as observed in 

 the few older stipes collected, showed no such origin. They 

 are irregular as to width and position, sometimes encircling the 

 stipe, sometimes appearing on one side only. Some partial 

 annulations were apparently due to a change of direction of the 

 filaments of the medullary layer. Most of the filaments of one 

 layer ran in a direction perpendicular to those of the next layer. 



In other instances the annulations were apparently due to an 

 overgrowth covering a primary cortical layer. The epidermis 

 of the inclosed layer was somewhat disorganized and the gela- 

 tine was filled with diatoms which thus became imbedded some 

 distance in the stem. Several layers of cortex and epidermis, 

 distinctly marked by their imbedded parasites, appeared on one 

 side of some stipes. In these instances the buried epidermal 

 cells were very distinct. 



LAMINA. 



The lamina is made up of the same three tissues, an epider- 

 mis from three to five cells in thickness, a cortex two or three 

 cells deep and a pith strand occupying the main cross section 



(figS. 12, 13). 



The leaf is abruptly thickened at the margin, due mainly to 

 the greater number of cells in the pith strand and cortical layer 



(fig- **) 



FRUIT. 



The cystocarps form dark dots showing through the surface 

 of the thallus when held to the light. The mature cystocarp 

 increases only slightly the thickness of the lamina in the center 

 of which it lies. The spores are of rounded but rather irregular 

 form, many of them enclosed together in a compartment-like 

 portion of the cystocarp formed by a single row of long clear 

 cells (Jig. 75). The cystocarp had no well defined wall as 

 described by Carruthers for Rhodymenia. The spores are dis- 

 charged by a rupture of the epidermal layers of the lamina just 



