1922] RANDOLPH—MAIZE 373 
50. Mortier, D. M., Chondriosomes and the primordia of chloroplasts and 
leucoplasts. . Botany 32:91-114. pl. I. 191 
, On certain plastids, with special reference to the protein bodies of 
Zea, Wika: and Conopholis. Ibid. 35:349-365. pl. 15. 1921 
52. RupotpH, K., Chondriosomen und Chromatophoren. Betting zur 
Kritik der Chundicesienthaotien. Ber. Deutsch. Bot. Gesells. 30:605- 
629. pl. 78. fig. I. 1912 
. SAPEHIN, A. A., Usitereaeheien iiber die Individualitét der Plastide. 
Arch. Zellf. 13: ae pls. 10-26. 1915. 
54. SCHERRER, A., Untersuchungen iiber Bau und Vermehrung der Chromato- 
phoren und das Vorkommen von Chondriosomen bei Anthoceros. Flora 
107:1-56. pls. 1-3. 1914. 
. TJEBBES, K., and Koorman, H. N., Erfelijkheidsonderzockingen bij 
boonen III. Albinisme. Genetica 1:532-538. 1 
. Twiss, W. C., A study of plastids and mitochondria in Preissia and corn. 
Amer. Jour. Bot. 6:217-234. pls. 23-24. 1919. 
51. 
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EXPLANATION OF PLATES XI-XVI 
All figures were drawn at the level of the table with the aid of an Abbé 
camera lucida under a Spencer objective, 1.8 mm., N.A. 1.25, with compensat- 
ing ocular 18. They have been reduced approximately one-third and show a 
magnification of about 2250 diameters. Observations of critical stages were 
made with a Zeiss apochromatic objective, 2 mm., N.A. 1.40, with compensat- 
ing ocular 6. 
PLATE XI 
Normal green plant 
Except where noted, drawings are of living cells of subepidermal tissue 
from mesophyll region of leaf, or of meristematic cells which will later become 
part of mesophyll tissue. 
Fic. 1.—From promeristematic region of germinating seed. 
Fic. 2.—From tip of first leaf bud formed from apex of stem; median sec- 
tion. 
Fics. 3-6.—Developmental stages from meristematic tips of successively 
older embryonic leaves; figs. 3-5, median sections; fig. 6, section through cyto- 
plasmic layer just beneath cell wall; largest proplastids in fig. 6 faintly green. 
Ics. 7, 8—From 16mm. embryonic leaf just before it emerges from 
sheath, showing cytoplasmic layer beneath cell wall in face view. 
Fic. 7.—Cell near tip, green color appearing in proplastids. 
Fic. 8.—Cell somewhat farther back from tip, proplastids more fully 
developed. 
Fic. 9. oe rom mesophyll tissue of fully developed seedling leaf, plastids 
bright gree 
