82 INDIAN FOREST MEMOIRS. 



The question as to whether, or not, a sucking insect is invariably the primary cause of the 

 injury however requires further investigation. 



The injury is most frequently found at the leaf insertions where the insect, or fungus, 

 probably intercepts the food materials on their way from the leaf into the culm. This 

 interference with the normal nutrition of the culm results in the internode next above the 

 attacked leaf -insertion becoming fistular instead of solid and being unusually small, weak 

 and more or less imperfectly nourished. When the internode is much weakened in this 

 way it is frequently unable to withstand the action of the wind and the upper portion of 

 the culm, with the terminal panicle, then bends over, but usually still remains attached to 

 the plant. Such a culm looks as if it had been half -broken by a passer-by. The panicle 

 branches also of culms injured in this way are remarkably tenacious and the spikelets are 

 persistent. Such a panicle therefore forms a striking contrast to a normally matured 

 panicle and has a characteristic and distinctive appearance both when seen in the forest 

 and in the herbarium. The normally-matured panicle shows a persistent main rachis 

 with closely adpressed fragile branches which rapidly break up and fall off, the pedicelled 

 spikelets falling first from their pedicels and the sessile spikelets following with the joints 

 of the branches and branchlets, while, so long as the spikelets remain, the callus hairs give 

 the panicle a purple colour. The abnormal panicle, on the other hand, shows persistent 

 and often spreading branches and persistent spikelets, while the callus hairs are frequently 

 pale to almost white and thus give the panicle a pale, or brownish, feathery appearance. 

 See Plate XXIII, fig. 3, and compare with the normal panicles shown in fig. 2. 



In these abnormal flowering culms of this species therefore we have a combination of 

 two remarkable and important characters, viz. the fistular culm and tenacious rachis of the 

 panicle branches, and the writer has seen panicles of this description placed under S. fuscum 

 Poxb. 1 in herbaria. The latter species, however, apart from other characters, can be at once 

 distinguished by the fact that both spikelets at each node are clearly pedicelled and the 

 spikelets eventually fall off 'from the tips of the pedicels, leaving the persistent panicle 

 branches intact, a state of affairs which is not seen in the abnormal panicles noted above. 

 See Plate XXV, fig. 11. 



Whereas the spikelets of a normally-matured panicle of the present species contain 

 the normal fully-formed fruit (grain), those of the abnormal panicles either contain a very 

 small and imperfectly developed fruit, or else the entire unexpanded flower with ovary and 

 stamens, thus indicating that the development of the flower and fruit has been prematurely 

 checked. 



The glumes of these abnormal panicles show no marked peculiarity. Saccharitm 

 porphyrocomum, Hackel, is founded on No. 19285 Herbarium H. F. Hance. The type is in 

 the Herbarium of the British Museum and has been examined by the writer. It consists 



1 In F. B. I. Saccharum fuscum Roxb. is said to occur in the upper and lower Gangetic Plains, and Duthie (Fodder Grasses of 

 Northern India, 1888, p. 23), says that it occurs "in the plains of Northern India * * * usually in damp spots." The writer has at present 

 no personal knowledge of this species in the field, and the only specimens in Herbarium Pehra are from A.ssam. Specimens and information 

 regarding this grass will be welcome at Dehra Dun. 



[ 82 ) 



