Index . 
xi 
Figures. 
4, 5* 
6, 7. 
1. 
2 . 
1-8. 
9 - 22 . 
23-27. 
2 8 . 
29 - 34 * 
35-39* 
40-48. 
49-62. 
63-77* 
78-90. 
91-96. 
97-100. 
101-106. 
107-113. 
1. 
2, 3* 
PAGE 
4. Longitudinal reconstruction of the xylem of Cone C of E. hyemale. 5. Longi- 
tudinal reconstruction of the xylem of Cone A of E. giganteum (Browne) . 243 
6. Longitudinal reconstruction of the xylem of Cone B of E. giganteum. 7. Longi- 
tudinal reconstruction of the xylem of Cone C of E. giganteum (Browne) . 244 
A and B, Cosmarium curtum, (Breb.) Ralfs. C-E, C. achondroides, West (Carter) 271 
A and B, C. formosulum, Hoff. c-F, C. praemorsum, Breb. G and h, C.Turpinii, 
Breb. (Carter) 279 
1, 2, 3. Successive stages in the growth of the normal seedling, showing the whorl 
of four laternal roots at the junction of hypocotyl and tap-root. 4 a. Older seedling 
viewed in plan, showing the relationship of the cotyledons and the epicotyle- 
donary leaves at the first two nodes. 4 b. The same in lateral view, one cotyledon 
removed. 5 a, b , c. Different aspects of a typical syncotyl for comparison with 
Figs. 4 a , b. 6. Side view of a Group II seedling. 7 a, b. Two views of 
a Group II seedling with peltate cotyledon. 8 a, b , c. Seedling with unequal 
cotyledons and a whorl of three asymmetrically placed rootlets (Holden) . 322 
9-19. Typical examples of syncotyls showing modification of general habit and 
venation. 20, 21 a, b. Typical Group II seedlings. 22 a , b. Group II seedling 
with a whorl of four roots and a tetrarch symmetry (Holden) . . . 323 
The distribution of the vascular strands in the young epicotyl (Holden) . . 325 
Diagram indicating the course of the bundles in the young epicotyl (Holden) . 326 
Syncotyl showing the suppression of one lateral bundle on the symphysis side 
and the compression of the leaves at the second epicotyledonary node (Holden) 328 
Typical advanced syncotyl showing suppression of both laterals on the symphysis 
side and delay in the fusion of the lateral and marginal bundles (Holden) . 329 
40-43. Young epicotyl in syncotyl showing reduction of one leaf of the basal pair 
and the modification of its bundle distribution. 44-48. Young epicotyl of 
seedling with unequal cotyledons (Fig. 8) showing bundle distribution 
(Holden) 331 
49-52. Epicotyl of syncotyl showing total suppression of first epicotyledonary 
leaf on the symphysis side and two leaves only at the third node. 53-5 7. 
A similar type of epicotyl in a Group II seedling. 58-62. Cotyledon bundles 
from the same seedling, showing anomalous bundle situated in the same vertical 
plane as the double bundle (Holden) 332 
63-69. Simple type of Group II seedling, the cotyledon showing the structure of 
a single normal cotyledon and developing a diarch root-plate. 70-77. Group II 
seedling showing on the left delayed fusion of lateral and marginal bundles and 
on the right independence of the two (Holden) . . . ' . . 333 
78-83. Group II seedling showing a further advance on that shown in Figs. 70-77, 
but still producing only a diarch root. 84-90. Group II seedling showing a still 
further advance leading to tetrarchy in the root (Holden) .... 335 
Anomalous Group II seedling with peltate cotyledon (Fig. 7), showing abnormal 
bundle behaviour (Holden) 336 
97, 98 illustrate the details of xylem and phloem distribution of Figs. 93 and 95. 
99. Tracheidal hypocotyledonary complex developed prior to the giving off of 
the basal root whorl from a syncotyl. 100. Typical diarch plate in a Group II 
seedling (Holden) 337 
Epicotyls of two Group II seedlings showing considerable modification of the leaf 
arrangements. 1 01- 105 are from one seedling and 106 from a second (Holden) 338 
Transverse sections of seedling with two unequal cotyledons (Fig. 8), showing 
suppression of the median double bundle in one cotyledon and the development 
of asymmetrical triarchy in the hypocotyl (Holden) ..... 340 
Amounts of carbon dioxide absorbed per square metre during two-hour periods by 
a detached sugar-cane leaf on May 14, 1918 (McLean) ..... 374 
2. Ditto absorbed per square metre each two hours by two pinnae of coco-nut on 
May 23, 1918. 3. Ditto by two pinnae of coco-nut (lower graph) and spread 
of edges of pinnae (upper graph) on May 16, 1918 (McLean) .... 377 
