Index 
xv 
Figures. page 
each leaf. 43-9. Transverse sections through a petiole in which a slightly more 
complex type of fusion of the adaxial bundles with the abaxial constituents occur. 
44-9 are from the petiole which is fellow to that shown in 43, the adaxial bundle 
on the right behaving similarly, while that on the left shows a still further com¬ 
plexity (Holden and Bexon).582 
50-5. Transverse sections of a petiole in the upper part of which three feebly developed 
medullary bundles occurred locally, but died out at a lower level without fusion. 
The one persisting longest (51 a) was represented by phloem only for the greater 
part of its course. 54 and 55 show the bundle fusions near the base of the petiole 
(Holden and Bexon).583 
56-60. 56-9. Transverse sections of a petiole, showing a single symmetrically situated 
medullary bundle (56) which at a lower level unites with half the adaxial bar (57). 
58 and 59 show differing methods of bundle fusion on opposite sides of the same 
petiole. 60. Diagrammatic representation of the vascular system of the young 
seedling shown as if cut through in the intercotyledonary plane and spread 
out flat (Holden and Bexon).584 
61-7. Series of semi-diagrammatic outlines, showing the transition features of seedling J. 
The small crosses in 63 and 64 mark the positions of the single protoxylem-like 
elements which appear sporadically in the hypocotyl; the arrow in 64 marks the 
position which would be occupied by Cpx . 2 if it had persisted (Holden and 
Bexon). 587 
68-74. 68-72. Diagrams illustrating the three types of transition from the cotyledons to the 
hypocotyl described in the text. 72-4. Comparative diagrams illustrating the 
transition features in Acer, Abronia, and Calycanthus (Holden and Bexon) . 593 
1. Typical broad bean seedlings after five days’ growth in a nutrient solution with or 
without boric acid (Warington) 633 
2. Broad beans grown in water-culture solution containing different quantities of boric 
acid (Warington) ........ • . . 636 
3. Total dry weight of broad beans (average of five plants). A. Grown without boric 
acid for different periods ; 1 : 50,000 then added. B. Grown with boric acid for 
different periods ; 1 : 50,000 then removed (Warington) .... 640 
4. Barley grown in water-culture solution containing different quantities of boric acid 
(average of five plants) (Warington) ...... . . 648 
5. Broad beans grown in pot culture with various quantities of boric acid mixed 
throughout the soil (average of five pots) (Warington) ..... 655 
6. Barley grown in pot culture with various quantities of boric acid mixed throughout 
the soil (average of five pots) (Warington) ....... 660 
1, 2. 1. Influence of drought on plasmolysis of Zygogonium ericatorum (Expt. XII). 
2. Effect of drought on Zygogonium (Expt. XVI) (Fritsch and Haines) . 692 
3, 4. 3. Effect of drought on Hormidium flaccidum (Expt. XXVI). 4. Ditto on Hor- 
midium-stage of Prasiola (Expt. XXVII) (Fritsch and Haines) . . . 695 
5. Influence of drought on plasmolysis of moss protonema (Expt. XV) (Fritsch and 
Haines).696 
6. Effect of drought on Pleurococcus Naegelii (Expt. XXX). Material soaked with 
water after nearly four weeks (Fritsch and Haines) ..... 699 
7. Recovery from plasmolysis in a sealed slide. The heavy lines show the results for 
Zygogonium (Expt. XVI), the thin lines those for moss protonema (Expt. XV) 
(Fritsch and Haines) . 702 
8. Recovery from drought in the case of Zygogonium (Expt. XVI) (Fritsch and 
Haines) . 7°9 
ERRATA 
Page 400, Fig. 9, for Condiophores read Conidiophores. 
„ 423, Fig. 23, for solution read solutions. 
„ 451, 1. 8, for sixty read sixty-two. 
