220 BOTANICAL GAZETTE [SEPTEMBER . 
Fic. 19.—Longitudinal section of lower part of embryo emerging from 
eS 
Fic. 20.—Transverse section of the vascular plate of hypocotyl. 225. 
Fic. 21.—Diagram representing rise of cotyledonary bundles from vascular 
plate. : 
Fic. 22.—Diagram showing origin and course of first leaf traces. 
Fic. 23.—Diagram showing origin and behavior of traces of second leaf. 
Fic. 24.—Horizontal diagram of cotyledonary node. 
Fic. 25.—Same node in plants developed on clinostat. ae 
Fic. 26.—Transverse section slightly above cotyledonary node showing the 
four main cotyledonary bundles and the three groups of foliar bundles. eh 
Fic. 27.—Longitudinal section of embryo somewhat less developed than 
one represented in fig. 19. ro. : 
Fic. 28.—Transverse section of stele of hypocotyl 2™™ above the section 
represented in fig. 20. 225. ; : 
IG. 29.—Transverse section of stele of hypocotyl immediately below oy 
ledonary node. X225. 
Fic. 30.—Transverse section of plant with median bundle of aborted cotyle 
don fairly well developed. Same level as jig. 26. X8. ; x8. 
Fic. 31.—Section of same plant 140 » above that represented in fig. ee tyle 
Fic. 32.—Detail of portion of axis 0.2™™ below fig. 39, between Be h gave 
donary bundle B and the phellogen; shows group of cambium cells whic 
rise to anomalous strand z. Kae ted in base 
Fic. 33.—Transverse section of the anomalous strand represented | 
of cotyledon in fig. 30. Xx 35 ns 
Fic. 34-—Cotyledonary node of plant with median bundle of aborted cotyl 
don well developed. 150. phloem 
Fic. 35.—Stele of hypocotyl 0.36™™ below fig. 34; xylem and 
collected in ring. Xr150. king 
Fic. 36.—Section of stele of same plant o.16™™ below jig. 353 shows b 
apart of phloem opposite the protoxylem. x50. «of metaxyiell 
‘Fic. 37.—Same, o.2™™ below the previous section; separation 0 
7 lateral 
f 
Fic. 38.—Section of root stele between the third and fourth whorls 0 
roots. X179. -orentiation 
Fic. 39.—Section of stele near root tip at beginning of diff 
of xylem. X225. : tertiary 
Fic. 40.—Transverse section of stele of lateral root showing exit of @ 
root. X225. “+ forma 
Fic. 41.—Longitudinal section of seedling showing beginning of root 
tion. Xro. 3 
Fic. 42.—Detail of beginning of root formation. 60. pocoty! 
a . . hypoe 
Fic. 43.—Detail showing interruption between vascular tissues of 
and root. Xr120. 
