194 STUDIES IN INDIAN SUGARGANES 



1916 and 1917 crops , so noticeable in. the joint and leaf sheath, appear to have 

 had less play in the lamina, and the similarity of the figures obtained in 

 differen.t observations is sometimes very striking. The persistei\ce of 

 differences in roughness, hairiness, venation, etc., would tempt one to make a 

 series of observations with stomata, but this has not been accomphshed, yet 

 the surmise may be hazarded that one more useful distinguishing character 

 may be expected from a study of these. The characters studied naturally 

 divide themselves into those which are capable of measurement an.d those 

 which are n.ot. The latter, which are less complicated are taken first. 



(1) Channelling. This infolding of the leaf at the base is a marked cha- 

 racter of the Saretha group, in wliich it resembles the wild Saccharutn S]Jon- 

 tanemn. The channelling is chiefly developed in the midrib but is not confined 

 to it, and the lamina takes a more or less distinct part in all the varieties of the 

 group. In the Sunn.abile series the channellin.g is not usually so marked and 

 it is confined to the midrib, while the lamina is flat to the base. 



(2) Callus. This term is apphed to the region of the lamina on each side 

 of the midrib just above the Hgule. It corresponds with the transverse marks 

 of lighter colour on the back of the leaf. This part of the leaf differs a good 

 deal in the two groujss under discussion. The callus is not well marked in 

 varieties of the Saretha series, it is usually covered by waxy outgrowths and is 

 often puberulous or pubescent. In the Sunnabile group, it is more marked, 

 often very distinct on each side, sometimes raised. It is usually covered by a 

 dense or shaggy pubescence and sometimes has long hairs at the sides nearest 

 the leaf edge. A study of the transverse marks, on the other hand, has not 

 yielded any appreciable differences in the two groups. 



(3) Scabrous feel. This is often a marked character at the tip of the leaf. 

 It is especially noticeable on the upper, ventral aspect, in the members of the 

 Sunnabile group. If one passes the fin.gers downwards in this region, the 

 roughness of the leaf , depending on small sihceous points projecting upwards, 

 reminds one of shagreen. There is also considerable, but less marked, rough- 

 ness on the lower or dorsal side of the leaf tip. One marked exception, however, 

 occurs, the leaf ends being practically glabrous in Pulli Khajee. This is in 

 fact similar to the Saretha group generally. The scabrous feel is very sHghs 

 or absent above in this group and the roughness below is sHght. In this 

 character of the leaves the Saretha series, as usual, resembles Saccharum 

 spontanewn in such specimens as have been examined. 



