268 



II. NOTES ON THE PHYSIOLOGICAL ANATOMY OF 



THE SHOOTS. 



As far as I have been able to find, no description of the anatomy of the six 

 plants used in these experiments has been pubHshed with the exception of Atriplex 

 vesicarium. The observations have been confined chiefly to the tissues con- 

 cerned in the water relations of the plants, and in most figures no attempt has 

 been made to fill in histological details. All the figures are drawn from camera 

 lucida outlines. 



Fig. 9. ; 



Transverse section of the assimilating 



shoot of Casuariira Icpidophloia. 

 s.c, Sclerenchyma ; Ii, Branched hair ; 

 s., Stomate ; cli., Chlorenchyma ; t.c, 

 Transfusion cells ; l.t., Leaf - trace 

 bundle; 7;;./-., Medullary rays; /., Phloem 

 fibres ; p.li., Phloem ; .v., Xylem ; u'.s.t., 

 Water-storage tissue. X66. 



Casuarina lepidophloia. (Fig. 9.) 



This tree is very common around Dilkera and frequently attains a height 

 of 30-40 feet. Attention was confined to the anatomy of the green assimilatory 

 shoots. These stand erect and are usually from 6 to 12 inches in length with 

 twelve ribs, the grooves running the whole length of the shoot. The anatomy 

 of the Casuarineae as an Order has been surveyed by Morini (1894), and to this 

 account C. lepidophloia conforms generally. It shows, however, xerophytic 

 features to a remarkable degree. This is noticeable particularly in the extreme 

 "woodiness" of the shoot. For the sake of comparison the tissue outlines of 

 C. distyla (a species occurring in the Mount Lofty Ranges, Kangaroo Island,, 

 and other places with a rainfall of 25-30 inches), and C. stricto (which has a 

 wider distribution) are appended (figs. 10 and 11). It will be seen that there 

 is a progressive development of lignified tissues in passing from the relatively 

 mesophytic C. distyla through the intermediate C. stricfa to the xerophytic C. 

 lepidophloia. 



