49 
31. Three spores seen in optical section showing spines, thickness of wall 
and slightly granular and guttate ? contents, x 500. 
(Figs. 32-40 showing germination of spores of Ustilago boitlelouw in 
distilled water on slide in damp chamber 24 hours at 37° C.; col¬ 
lected December 20, 1888, germinated February 20, 1889.) 
32. Spore showing cleft in the wall and young promycelium, x 500. 
33. Spore bearing a branched promycelium which has split the cell-wall and 
about to produce a sporidium on the side (?), x 500. 
34. Spore showing two promycelia, the one scarcely developed, x 500. 
35. Spore seen in optical section showing a slender promycelium apparently 
connected with the contained gutta, x 500. 
36. A spore with a more mature promycelium which is either branched and 
bearing a sporidium at the end of the branch, or a primary sporidium 
is producing a secondary one, x 500. 
37. A free sporidium budding, x 500. 
38. A promycelium broken off from the spore, bearing two sporidia from be¬ 
low the septa, x 500. 
39. A free promycelium bearing a single sporidium, x 500. 
40. .A slender free promycelium producing a single sporidium, x 500. 
Plate II, 
Fig. 1. Cross-section of cells of normal ground tissue ; a, intercellular spaces. 
2. Longitudinal section of cells of normal ground tissue. 
3. A section of a nortion of the normal epidermis with the underlying parts; 
a, epidermal cells ; b, sub-epidermal layers; c, cells of the ground tissue. 
Plate III. 
4. Cross-section of a normal fibro-vascular bundle; a, intercellular canal; 
b , annular vessel; c, pitted ducts; d, phloem; e, elements of the bundle 
sheath. 
5. Longitudinal section of a normal bundle ; a, cells of ground tissue; b, ele¬ 
ments of bundle sheath ; c, cambifonn cells; d, sieve tubes ; e, tracheid; 
/, portions of an annular vessel; g, intercellular passage; h, wood pa¬ 
renchyma. 
Plate IV. 
6. Longitudinal section of normal epidermis ; a, large; b, small cells of epi¬ 
dermis ; c, sub-epidermal cells. 
7. Surface view of normal epidermis; «, large ; d, small cells; b, guard cells; 
and c, accessory cells of the stomata. 
8. Diagram of a section of a stem with the abnormal growth ; a, b, stem; c, 
abnormal growth; e, bundles; d, region of active growth. The light 
shading represents ground tissue cells, the dark shading masses of 
spores, and the lines in cthe bundles sent out to the abnormal growth. 
9. Section similar to that represented in Fig. 3, except that it is slightly dis¬ 
torted; a, epidermal and sub-epidermal layers; b, ground tissue cells; 
c, portion of a bundle. 
10. Surface view of epidermis of abnormal tissue; a, epidermal cell; b, nu¬ 
cleus. 
11,12. Surface view of abnormal tissue showing distortion of stomata ; a guard, 
cells; b, accessory cells; c, epidermal cell. 
20414—No. 1-4 
