134 
14. The dark color of the outer coat or rind; number of cells 
thick; the white color of the medulla. 
Detail in a DRAWING the structure of the sclerotium. 
Saprogenesis. These sclerotia, when mature, fall to the ground or 
find their way at threshing into bins along with the rye grains. With 
these they may be sown and find their way to the soil. Here they remain 
dormant until spring, when the fungus again becomes active. At any 
point beneath the rind, growth-centers may be set up from which are 
developed slender stalks with globose tops. These are developed at the 
expense of the food-materials stored in the cell-walls of the sclerotial 
medulla. 
Examine the so-called germinating sclerotia provided, OBSERVE :— 
15. The small, capitate bodies arising from the sclerotium,— 
the stromata. Note the comparative size of the stem and the head. 
Examine the stromata carefully with a hand-lens, noting the small dots 
or punctations. Make a prawinc to bring out all the external characters 
of the stromata and how they arise from the sclerotium. 
Prepared slides of cross-sections of the stromata are furnished. 
Examine with the low- and high-powers and OBSERVE :— 
16. The ovate acuminate cavities,—perithecia. Note the dense 
pseudoparenchymatous wall. 
17. The location of the perithecia about the periphery. | 
18. The opening at the top,—ostiolum. Note that it pro- 
trudes. Make an outline prawinc of the cross-section of the entire 
stroma. 
19. The asci arising from the bottom of the perithecium. 
20. Within the asci, the bundle of eight thread-like spores. 
Supplement at this point with the crushed mount prepared under number 8. 
Stain by running a little methyl blue under the cover-glass. 
Make an enlarged DRAWING of a perithecium containing the asci; 
and of a single enlarged ascus with the ascospores. 
Secondary Cycles initiated by the conidia of the Sphacelia stage, 
multiply and spread the pathogene during the blossoming-period of the 
host. The Sphacelia stage, followed by the development of the ergot, is 
produced as in the primary cycles. 
REPORT 
; 1. Make one or more cartoon-like sketches to illustrate the life- 
history of Claviceps purpurea (Fr.) Tul. 
