Apr. i-June 24, 1918 I llustf atioilS ^ JX 



Page 

 Plate 39. Bacterium marginalc: 'A. — Part of a leaf from one of the original 

 plants as received, showing the brovvn veins in the infected and shriveled 

 margins. B. — Part of a lettuce leaf, showing the shriveling and the mar- 

 ginal brown venation produced by spraying with Bact. marginale on March 



2. 1917 "■ 388 



Plate 40. Bacterium marginale: A. — A head of lettuce showing the marginal 

 infection on tender leaves in center. Inoculated by spraying on March 2, 

 1917. B. — Four lettuce leaves inoculated by spraying February 21, 1917. 388 

 Plate 41. A. — Bacterium vitians: Cross section of stem showing bacteria in 

 place. B. — Bact. vitians: Polar flagella stained with Casares-Gil 's flagella 

 stain; from a young agar culture. C. — Bact. vitians (Virginia): Polar 

 flagella stained with Casares-Gil 's flagella stain. Eighteen rods in this field 

 bear flagella. D. — Bact. marginale: Gro^^•n on agar for 2 days and then 

 stained with Ribbert's capsule stain. E. — Bact. marginale: Flagella 

 stained with Casares-Gil 's flagella stain. F. — Bact. ynarginale: Cross section 

 of a diseased, shriveled leaf showing bacteria in the tissues 388 



Chemistry and Histology of the Glands of the Cotton Plant, with 

 Notes on the Occurrence of Similar Glands in Related Pl.-vnts 



Plate 42. A. — Longitudinal section of a cotton seed, showing the internal 

 glands in the cotyledons and the radicle. B. — Longitudinal section of seed 

 of Ingenhouzia triloba, showing the internal glands as in Gossypium spp. 

 C. — Internal gland of a cotton seed, with secretion 436 



Plate 43. A. — Cross section of the hypocotyl of a cotton seedling, showing 



internal glands. B. — Gland of same 436 



Plate 44. A.— Longitudinal section of the hypocotyl of a cotton seedling, 



showing the internal glands. B. — Gland of same 436 



Plate 45. A. Cross section of a primary root of a cotton seedling, showing 

 internal glands. B. — Gland of same, the secretion having been removed 

 by alcohol 436 



Plate 46. A. — Cross section of a cotton bud, showing internal glands in (a) 

 calyx, {h) petal, (c) anther, {d) staminal column. B. — Cross section of a 

 young cotton boll, showing internal glands 436 



Plate 47. A. — Cross section of a woody cotton stem, showing internal glands 

 in the primary cortex (X), but none in the secondary cortex. B. — Cross 

 section of a phloem ray of a cotton root, shov%-ing two internal glands 436 



Plate 48. A-C. — Cross sections of the internal gland of cotton from the ovary 



in the bud, showing three stages of its development 436 



Plate 49. A. — Portion of a cotton leaf, showing internal glands, punctured by 

 aphids (surrounded by light area) ; also uninjured glands. B . — Cross section 

 of the midvein of a cotton cotyledon, showing rudimentary nectary 436 



Plate 50. A. — Cross section of the midvein of young true leaf of a cotton 

 seedling, showing the nectary and internal gland. B. — Nectary and in- 

 ternal gland of same 436 



Pox, or Pit (Soil Rot), of the Sweet Potato 



Plate 51. A. — Young sweet-potato roots affected with pox spots. B. — 

 Sweet-potato sprouts, the lower rootlets of which have been totally de- 

 stroyed by pox. C. — Typical pox spots on tubers of the Irish potato. 

 D. — Pox spots of the Irish potato (after Ramsey). E. — Pox on Irish potato 



showing lenticel infection 450 



56115°— 19 2 



