240 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



EXPLANATION OF PLATE XLL 



The figures were drawn with Abb6 camera over Leitz No. 7, or Zeiss 

 2 mm. apochromatic oil-immersion objectives, and Leitz eye-piece 3 or Zeiss 

 compensating eye-pieces 6 and 12. 



Ramalina reticulata. 

 Fig. I, a and b. Ungerminated spores in water : a, smaller than the average 



and probably unripe ; b, larger than the average, x 1300. 

 Fig. 2. Germinated spores, showing breaking up of the oil drops and their 

 re-formation in the germ-tubes ; both cells of each spore germi- 

 • nating. x 1300. 



Fig. 3. Germinated spore ; only one cell putting out germ-tube, but this 



branched, x 1300. 

 Fig. 4. Germinated spore ; germ-tube growing close to and straight past a 



healthy gonidium. Is actual contact needed to produce stim- 

 uli? X 650. 

 Fig. 5. Group of invested gonidia and one uninvested gonidium separated 



by grinding ; showing relative sizes of attached and unattached 



gonidia. x 650. 

 Fig. 6. Group of invested gonidia set free by grinding ; showing gonidia 



dividing internally into two. x 560. 

 Fig. 7. An invested gonidial cell dividing into four, x 560. 

 Fig. 8. A similar one showing four enclosed daughter-cells, x 560. 

 Fig. 9a. The same cell as fig. 8, twenty-four hours later, showing eight 



daughter-cells liberated by solution of wall of mother-cell. 



X 560. 



Fig. 9*. A gonidial cell containing a haustorium ; the protoplast contracting 



and thereby escaping from the haustorium. x 560. 

 Fig. 10. Similar to fig. 9*. x 560. 



Fig. II. Group of invested gonidia, showing two haustoria within gonidial 

 cells. X 650. 



Fig. 12. Isolated gonidium containing haustorium ; gonidium isolated and 

 hypha broken off by grinding, x 1750. 



Fig. 13. Gonidium, in a section, showing haustorium and the hyphal cell of 

 which it is a branch. 12 and 13 comparatively recently pene- 

 trated by haustoria. x 900. 



Fig. 14. Gonidium, isolated by grinding, entirely emptied by haustorium. 

 X 1750. 



Fig. 15. Gonidium, in a section, entirely emptied by haustorium and by 

 investing hypha. x 900. 



Fig. 16. Unusually large and healthy gonidial cell, free from investing 

 hyphae and showing chromatophores enclosed in peripheral 

 cytoplasm ; the central nucleus with its nucleolus and enclosing 

 cytoplasm with radiating strands, x 1750. 



Fig. 17. A gonidial cell dividing by internal cell-division into four daughter- 

 cells, each with its own central nucleus ; daughter-cells not yet 

 surrounded by their own cell-walls, x 1750. 



Fig. 18. Gonidial cell divided by internal cell-division into eight daughter- 

 cells, each with its own central nucleus and its own cell-wall. 

 X 1750. 



Usnea. 



Fig. 19. The central body, nucleus, of a gonidial cell dividing, preliminary 

 to the division of this invested gonidial cell, x 1750. 



Sphcerophorus globiferiis. 

 Fig. 20. Somewhat later stage in the division of the central body, nucleus, 

 of an invested gonidial cell, x 1750. 



