^ _ 



"iJ 



472 



DR. A. ARBER OX THE LEAF-TIPS 



(g) seen in th 



A little liiglior, on the other hand, the sheath closes into a solid, more or 



') 



A ctn-ious feature is the occurrence 



of the sniiiU structure which I have marked ?., and which I think^ may 

 possihly he interpreted as a li<^ule, but this cannot bo decided without 

 further uiaferial. This special point, to which I want to draw attention 

 here, is the petiolar character of the anatomy of this apex, which is particu- 

 larly obvious in fig. 13, drawn from a second spathe. The arrangement of 



Figs. 12-13, 



SPATHE LEAVES OF 



LUDOVIA 



c 



Figs. 12 & 13. Lndovla crenifoUa, Dr. ; 



transverse sections through 



Fig. 



spathe-leave3(xl4).— Fi- 12 a-d, series fiom one apathe. 

 tip of another spathe ; ^ = gum-canals ; l.= ' " 



apical region of 

 13. Section from 



? ligule. 



the bundles recalls that met with in certain Acacia phyllodes, whose petiolar 

 nature is generally accepted, as well as in various "equitant" leaves 

 which I have previously interpreted as phyllodic *. 



3. Pseudo-Jamlmvoftlie Type of Sniilax aspera, L. 



A number of Monocotyledonous leaves are differentiated into a sheath, 

 stalk, and disiinct blade. I have given reasons elsowliere f for regarding 

 this 'blade as a mere flattening or expansion of the distal region of the 

 petiole, and have i)roposed for it the name, "pseudo-lamina," to distinguish 

 it from the true lamina of the Dicotyledon. In certain cases the limb 

 of such a leaf terminates in a solid apex, resembling those of the simpler 

 leaves wo have been considering. Such an apex is specially characteristic 



* Arber, A. (1918), pp. 482-G. 

 t Arher, A. (1918). 



