Oct. i, 1920-Mar. 15, 1921 



Illustrations XI 



52. A, C, B.—Urophlyctis pluriannulatus . B.—Urophlyctis alfalfac. A — 



Portion of actively growing thallus of U. pluriannulatus dissected from 

 gall on leaf of Sanicula menziesii, including a turbinate cell ta with a 

 nearly mature resting spore ra. B.— Abnormally enlarged hyphae and 

 turbinate cells of U. alfalfae, showing conspicuous thickening of the 

 walls. C— Peripheral portion of actively growing thallus of U. pluri- 

 annulatus, similar to A, showing 8 turbinate cells of the second order, 

 of which 7 have produced turbinate cells of the last order as well as 

 resting spores. D— Nearly mature resting spore of U. pluriannulatus, page 

 viewed from polar end, showing 22 haustoria in zonate arrangement. ... 324 



53. Urophlyctis pluriannulatis: Section of leaf of Sanicula menziesii, showing 



development of parasite within gall 3 2 4 



54. Crowns of alfalfa plants bearing galls caused by Urophlyctis alfalfae photo- 



graphed at different stages of development. A.— A comparatively early 

 stage of development at which the origin of the gall structures from the 

 elements of developing buds can be traced. B— A later stage of devel- 

 opment at which the origin of the tissue has become obscured 324 



55. A comparatively early stage of host reaction to invasion by Urophlyctis 



alfalfae ." 324 



56. A.— Late stage of development of host reaction to the invasion of Urophlyctis 



alfalfae. B — Vertical section through a well-developed gall near its 

 central axis, showing its laminated structure arising from the thickening 

 of bud elements 3 24 



Pathological Anatomy ok Potato Blackleg 



Text Figure 



1. Section of potato leaf, showing distribution of protein crystals 329 



Plates 



57 . A.— Plant affected with blackleg. B— Section of single upper epidermal 



cell of leaf and adjacent palisade cell. C— Section of pith cell which is 



transformed into a sclereid adjacent to phloem fibers 33° 



58 _ a.— Pith cells of petiole transformed into sclereids with typically stratified 



walls. B .—Vascular tissue of the petiole greatly increased by blackleg. . 330 



Sclerotica minor, n. sp., the Cause op a Decay of Lettuce, Celery, 



and Other Crops 



Text Figure 



1. Camera lucida drawings of 5. minor: A, Microconidia and conodiophores; 



B, Ascospores; C, Germinating ascospores; D, Asci and paraphyses 33 2 



Plate 



59. A.— Sclerotia on hard potato agar: center, Sckrotina liberiiana, either end, 



5. minor. B— Apothecia of S. liberiiana. C .— Apothecia of S. minor. . 334 



Relation of the Soil Solution to the Soil Extract 



Text Figures 



1. Graph showing relation of freezing-point depressions in soil (calculated to 

 22 per cent moisture) to total solids extracted by 5 parts of water to 1 of 

 soil 382 



