INTEODUCTION xxiii 



up into trees. "^ What becomes of the permanent imdershrubs here described, 

 when the area is protected against fire; is not known ; probably they are 

 smothered by t he surrounding vegetation. That some of these undershrubs 

 were cu.ltivated long ago in the Calcutta Botanic Grarden is evident from 

 Eoxburgh's Mora Indica^ but no record exists whether they had changed 

 their habit when no longer exposed to the regime of annual fires. 



In the old Forest Flora of North- West and Central India I drew attention 

 to a number of these remarkable undershrubs, and wrote regarding them on a 

 later occasion {Ind. For. XXVI. 10). It has given me great pleasure to find that 

 Mr. Duthie, in his excellent Flora of the Upper Gangetic Plain^ has fully 

 recognized the importance of these interesting species, and it is satisfactory that 

 in the Park of the Dehra Bun Forest School Ivanjilal has at my suggestion 

 commenced to cultivate a number (particularly Greicia sapida) in order to 

 see whether they will change their habits when no longer exposed to the 

 annual fires. It is possible, though not proved, that trees or large shrubs 

 may, by the continuous action of the annual fires, gradually have been con- 

 verted into undershrubs. Against this idea, however, stands the fact that 

 Careya herbacea^ Erytlirina resibpinata and most other species adverted to, 

 differ from the arborescent species of the same genus by very definite characters 

 in leaves, flowers and fruit. As far as known at present, Premna is the only 

 genus which forms an exception in this respect. No less than 5 undershrubs 

 are known in this genus, and 3 of these can hardly be separated by characters 

 other than habit from species which are trees or large shrubs (cf. P. 

 pinguis, P. amplectens and P. macrophylla^ p. 511), Similar undershrubs 

 are known from tropical Africa, and there are species in the Arctic regions 

 (Comics suecica, C. canadtnsis^ Rubus arcficitb), the shoots of which are killed 

 annually by the frost of winter, the underground rootstock remaining alive. 



I am fully aware that in speaking of these undershrubs and in describing 

 them in this book I lay myself open to the charge of inconsistency. At the 

 outset I said t1;iat the object of this book was entirely practical. I admit 

 that no forest revenue can be made out of these undershru-bs, and that they 

 are not likely ever to play an important part in the system of forest manage- 

 ment. But foresters who may cultivate these remarkable species will thereby 

 be induced more completely to study the laws which govern the habits of 

 plants and the conditions which may u.nder certain circximstances cause the 

 development and mutation of species. Indeed, I go fu.rther, and would ventui^e 

 to suggest that some of these remarkable undershrubs be cultivated in Indian 

 Forest Gardens, although they are not likely immediately to increase the 

 forest revenue. Their study may quite unexpectedly throw light upon 

 some important forest questions. At the present day this may be pro- 

 nounced fanciful by my young friends in India, and they may regret that 

 their old friend has indulged in such fancies. They will I hope relent when 

 they find practical suggestions of other kinds in this book, which I trust will 

 be of i-eal use to them in their work. 



It now remains to express my deep gratitude to all those who have assisted 

 me in this arduous work. During the progress of it I have had the great 

 privilege of discussing many important points with Sir William Thiselton- 

 Dyer, with Dr. Dukinfield H. Scott, Mr. W, B. Hemsley, Dr. Otto Stapf, Mr. 

 0. B. Clarke, and with Dr. Augustine Henry. Mr. James Eamsay Drummond 

 has kindly given me much valuable information regarding trees and shrubs 

 of the Punjab. To Mr. C. H. Wright, of the Herbarium, Kew, I am 

 indebted for the care which he has devoted to the index and for the assistance 

 he has given me in preparing the manuscript for the press and in correcting 

 the proofs. Mr. Martin Cole has been most useful in preparing excellent 

 microscopic slides whenever I required them. Several Indian officers, while 

 ^ Grewia scahrophylla at times is an undershruh, when exposed to the annual fires ', in 

 other places it grows into a tall shrub. Other shrubs probably behave in the same 

 manner. 



