156 XEROPHILOUS CHARACTERS OF HAKE A DACTYLOIDES. 



very strongly developed in plants exposed to dry conditions, and 

 particularly so in the Proteace?e(2). That they are effective in 

 enabling the plant to withstand the effects of a dry environment, 

 may be inferred from their common occurrence in such conditions 

 in plants of very diverse natural orders. 



REFERENCES TO LITERATURE. 



(1) Sachs, On the Physiology of Plants. 



(2) Hamilton, " On the structure of the leaf in Banksia sery-ata" Report 



Aust. Assoc. Adv. Sc. 1907. 



EXPLANATION OF PLATES IX. -X. 

 Plate ix. 

 Fig.l. — Venation of leaf,( x ^). 

 Fig.2. — Hairs on young leaf. 



Fig. 3.- Epidermis and one row of palisade cells of ordinary leaf; c, cuticle. 

 Fig. 4. — Epidermis and one row of palisade cells of shade-leaf; c, cuticle. 

 Fig.5. — Section of stomate and vestibule; v, vestibule; g, guardcells. 

 Fig. 6. — Capitate hair in cavity; a, projection of epidermis into mesophyll. 

 Fig.7.— Ditto. 



Fig.8.— Simple scleroblasts; a, cavity. 

 Fig.9. — Massive, branched scleroblasts; a, cavity. 



Plate X. — Microphotographs. 

 Fig.lO. — Cross-section of ordinary leaf; c, cuticle; s, scleroblasts. 

 Fig.ll. — Cross-section of shade-leaf ; c, cuticle; s, scleroblasts. 

 Fig. 12. — Section parallel to plane of leaf; s, scleroblasts cut at right angles. 



