Oct. i. 1920-Mar. is, 1921 Illustrations xin 



Influence op Temperature and Humidity on the Growth op Pseudo- 

 monas citri and its host plants and on infection and development 



of the Disease 



Text Figure 



1. Graph showing the rate of enzym action, as expressed in millimeters, at the p ag e 

 various temperatures for a period of eight days on soluble starch agar ... 451 



Daubentonia longifolia (Coffee Bean), A Poisonous Plant 



Plate 



6a. Herbarium specimen of Daubentonia longifolia, showing flowers, leaves, 



and pods 5 X 4 



Fusarium-Wilt of Tobacco 

 Text Figure 



1. Camera-lucida drawings of spore forms of Fusarium oxysporum var. nicotianae, 

 n. var.: A, macroconidia; B, microconidia; C, chlamydospores; D, coni- 

 diophore of the sporodochial stage 521 



Plates 



63. A. — A typical spot in a field of Maryland Broadleaf tobacco infested 



with Fusarium-wilt. Benedict, Md. 1916. B. — Uninoculated control. 

 C. — Plants grown in soil artificially inoculated with the tobacco-wilt 

 Fusarium and planted to White Burley 536 



64. A. — Plant infected with Fusarium-wilt, showing wilting in vertical line 



on stalk. B. — Last stages of Fusarium-wilt in Maryland Broadleaf 

 tobacco S36 



65. A. — Result of plating out five pieces of infected vascular tissue from infected 



plant, illustrating character of growth of mycelium on potato agar. 

 B. — vStem and midrib of plant, cut longitudinally to show the blackened 

 vascular system 53^ 



66. A. — Cross sections through vascular system of tobacco plant infected with 



Fusarium-wilt, showing the fungus mycelium in the vessels. B. — Longi- 

 tudinal sections through the vascular system of plants infected with 

 Fusarium-wilt, showing the fungus strands in the vessels 536 



67. I. — Plants illustrating the influence of soil temperature on degree of wilting 



of plants in soil infested with Fusarium-wilt. II. — Plants grown in the 

 same soil uninfested and at corresponding soil temperatures. 

 III. — Plants illustrating the influence of varying soil reaction on the 

 amount of Fusarium-wilt in infested soil. IV. — Plants illustrating 

 varietal differences in resistance of tobacco to Fusarium-wilt 536 



Nodule Bacteria of Leguminous Plants 

 Plates 



68. A. — Soybean bacteria, J. K. Wilson's strain, 4 days old. B. — Vetch bac- 



teria, 3 days old. C. — Bacillus radiobacter, 2 days old. D. — Soybean 

 bacteria, beef agar, 4 days old. E. — Red clover bacteria, beef agar, 

 4 days old. F. — Bacillus radiobacter, beef agar, 4 days old. G. — Cowpea 

 bacteria, potato, 6 days old. H. — Red clover bacteria, potato, 14 days 

 old. I. — B. radiobacter, milk, 7 days old. J. — Cowpea bacteria, man- 

 nite-nitrate agar, 8 days old. K. — Vetch bacteria, mannite-nitrate agar, 

 8 days old. L. — B. radiobacter, mannite-nitrate solution, 17 days old 556 



