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8. The number of germtubes produced from each spore. Are 
they septate? . . 
9. The densely granular protoplasm crowded into the tips 
of the long germtubes. The empty germinated spores. Compare with 
those not germinated. 
DRAW two or more germinated uredospores. 
The germtube enters through a stoma and forces its tip between the 
palisade-cells, sending haustoria into them, thus establishing a food-rela- 
tion with the host. Make thin cross-sections of a leaf through a sorus; 
clear in chloral hydrate; study and OBSERVE:— 
10. The intercellular mycelium; often in gnarled and inter- 
woven meshes, especially in the intercellular spaces, prying apart and 
isolating the host-cells; densely granular, septate. 
; 11. The peculiar lobed haustoria in the host-cells; their very 
thin walls and densely granular protoplasm. 
12. The uredinium; its structure and relation to the host- 
tissue. 
13. The matted mycelial bed from which arise the short closely 
crowded uredosporophores. 
14. The globose uredospores; thin walled, covered with short 
spines and much lighter colored than the one-celled teliospores, some of 
which are usually to be found in a uredinium. 
Make a prawinc of a portion of a cross-section to show the pathogene- 
structures and their relation to the host-tissue. 
The mycelium is supposed to spread very generally throughout the 
leaf- and stem-tissues beyond the point where distinct lesions appear, 
so that cuttings from diseased plants are usually invaded. It is believed 
that this habit of the pathogene is responsible for its wide and rapid distri- 
bution in this country. Make thin sections through the leaf at some dis- 
tance from the lesion; clear in chloral hydrate; examine and DETERMINE :— 
15. Whether or not mycelial invasion is general. 
Select a dark-colored sorus,—a telium (usually more abundant on 
stems); mount some of the teliospores. Study and oBSERVE:— 
16. That they are much darker in color than the uredospores, 
although of about the same size and shape; walls slightly thicker, and 
epispore nearly or quite smooth; stalk often still attached. DRaw several. 
The teliospores arise from the same mycelium on which uredospores 
are produced, usually more abundantly in the sori formed as the affected 
organ grows older. 
Saprogenesis. The teliospores do not germinate at once as do 
the uredospores, but require a period of rest. They are chlamydospores, 
and, under natural conditions, germinate in the spring producing a promy- 
celium with four sterigmata, each bearing a basidiospore (sporidium). 
Study the drawings provided. copy. 
These sporidia produced by the germination of the teliospores can, 
so far as known, infect only the Euphorbia host. As Euphorbia gerardiana 
does not grow in this country, the sporidia cannot function in the propaga- 
tion of the pathogene, and primary cycles cannot develop. 
REPORT 
1. Prepare a diagram showing the complete life-history of 
Uromyces Caryophyllinus (Schr.) Wint. as it may occur in Europe. 
