498 



THE TROPICAL AGRICULTURIST. 



[December i, 1882. 



opinion as to the true life history, which he held 

 had never been accurately understood or described. The 

 results of his researches into the nature of this fungus 

 as well as that of hemikia vaskUrix were imparted 

 to me in confidence, but it will be no breach of faith 

 on my part now to stafe that they eutirelj- upsotall 

 existing theories regarding tlie former and that he 

 considers Marshall Ward's life history of H. V. as 

 incomplete, if not inaccurate. It wdl be seen in 

 the colmuus of the '-Gardener's Chronicle" of 7th 

 ultimo, that hs is now giving the public the benefit 

 of his discoveries, and in subsequent papers he will 

 state his reasons for disagreeing with Mavahall Waid, 

 from which a controversy is sure to arise by which the 

 coffee planters must benefit. 



It will be uiuieoessary tor me, however, in replying 

 to " W " to rely on Wilson's discoveries. 



" W." gives a life history of the deadly fungus 

 (P. infesUmi] which is peculiarly his own or at all 

 events a theory which was discarded when it came to 

 be understood that Pcroiiospera was no disease, but 

 only the cause thereof, like Bemileia in coffee. His 

 motion that P. infeslam requires no open door to 

 send its germinating tube through, is not accurate ; 

 thebelief to this day being (Stephen Wilson expected) 

 that it enters the stoma on the under side of the 

 leaf and I know for a fact thai- it becomes hrst 

 visible there. The despaich and ease with which it 

 disposes of its over-hospitible host is readily ex- 

 plained by the nature of the host, it being of a suc- 

 culent cousistence of three months' growth, rendering 

 the ramifications of the mycelium, a very simple 

 matter, as compared with that of the HemUcia, which 

 is a perennial with its stem, root and branch cells of 

 a hard and close nature, difiering therein from its 

 own leaves and rootlets which become an easy prey 

 to the mycelium of M. V. 



Is it a fact that coffee rootlets have no stomata ; 

 some roots have. But even if it were satisfactorily 

 proved that they have not, is it necessary for the fruc- 

 tification of a spore that the germinating tuoe should 

 enter a stoma! I think not, for did not Marshall 

 Ward by depriving the le»f of its upper epidermis 

 and placing the spore on the leaf cells, prove tliat 

 germination in this manner was possible 'l It would 

 not be necessary that a spore germinating on a root- 

 let should fructify to acdmiphsh the destruction ot 

 the rootlet, the mere entrance of the tube would be 

 sufficient in a few hours under certain conditions to 

 effect this. Every planter knows that the rooia ot 

 his coffee trees are covered with a fungus. May this 

 not be another form of Iwmkia ? In short, with 

 our present limited knowledge of fungoid nature, can 

 any hard and fast Hue be laid down as to their pe- 

 culiar procliviiies ? Plowright has now proved that 

 the rust in wli.at is identical with that produced on 

 the barberry leaf, although tlie spores of the two are 

 somewhat different A spore taken from a barberry 

 leaf fructifies on a wheat leaf, but the fruit from this 

 will not again germinate on the barberry. Ihe spore 

 of barberry fungus grown on a wheat plant is entirely 

 diflferent from the original. As the editor of the tod- 

 ener's Chronicle says in reviewing Stephen Wilso"^ 

 paper on potato fungus [referring to fungij the 

 more then- history is studied the more complicated 

 does It appear to be. Their construction is simple— 

 of the simplest, in fact ; but their habits of lite are 

 astonishingly complex." These facts remain a fungus 

 is present on our roots, a great dearth of rootlets exists 

 which was CO- incident with the leaf fungus, what is 

 the connection between them ?— Yours faithtully,— J. t). 

 rWe suppose the scientific and the popular explanation 

 of deficiency of rootlets in coli-ee trees badly aliected by 

 leaf fundus iiss been identical : the debilitating uHects ot 

 thefuuiius has prevented the tree from elaborating root 

 lets in normal quantity. And no doubt the same cause, 



general debility, would render the root^ specially liable 

 to attacks of fungi. But this new theory that the root 

 fungi are identical in nature though different in form to 

 that which attacks tne leaves, is worthy of full in- 

 vestigation. Surely one of the main positions taken up 

 by Mr. Morris which Mr. Marshall Ward overthrew, 

 was that now apparently adopted by "J. S.," that the 

 mycelium of the fungus covered the stems of the trees ? — 

 Ed. J 



COFFEE CULTURE : A PLEA FOR WEEDS AND 

 FOR LIGHT PRUNING. 

 Dear Sir,— When laud is kept clean, I do not 

 care what the lay of it is, or how closely drained, 

 there is always a certain amount of wash. Weeds, if 

 returned to the soil, return what they have taken 

 from the soil, and add the ammonia and carbonic 

 acid that they have absorbed from the atmosphere. 

 Afaiu weeds absorb any superabundance of moisture 

 that may be in the soil, and they nut only shade 

 the soil but they also shade the roots ot tlie coffee 

 tree and keep them cool and moist and give the tree 

 time to evaporate tne sap gently, to elaborate it, 

 so that the breathing pores are not injured or disorgan- 

 ized by a sudden chmge from cloudy weather to 

 hot, bright sunshine and they so prevent disease. 

 Weeds do not exhaust land;* it is the coffee that 

 exhausts the Lind. If weeds exhausted land, aband- 

 oned land would in time become bare, instead of 

 which each succeeding crop of weeds becomes more 

 and more vigorous, till some jungle shrub creeps in 

 and they multiply, and, if left alone, would no doubt 

 in time revert to forest again. Clean weeding became 

 general since about 186i, from which dale coffee com- 

 menced to flicker, and how many places have gone out. 

 The proper thing for coft'ee is a carpet of weeds, and 

 keep it as a carpet, by either pulling up the big weeds 

 and leaving the small ones, or, as they do in some parts 

 of India, cut them with a grass knife, or, if we must do 

 without weeds, we must find something else. Thatch 

 is too dancerous. The coffee tree is a forest tree and all 

 forest trees have their roots shadedaudtheir tops exposed 

 to the sun. There is no limit to the growth of a tree ; 

 if there wS^ after a certain age every tree would be of 

 one uniform thickness. The richer the soil and larger 

 the quantity the more and more vigorous a tree be- 

 comes and produces fruit in proportion, but, when 

 there is a falling-oEE of the essential food, then the 

 tree loses the power of production ; a further falliug- 

 off, it loses the power of supporting its branches, and 

 if the supply is exhausted altogether, that tree must 

 die ; so thut, in manuring, the great object is not to 

 manure the tree but to enrich the soil. It does not 

 matter how and where it is placed, if within reach. 

 The same instinct, that makes a creeper find some- 

 thing to creep on, makes a tree know where there is 

 is good food to send its roots into. A tree sucks 

 up its food through its small tender fibrous roots 

 and the ouly use it makes of its larger roots 

 is to prevent its beiug blown down, (which I 

 do not think there is much fear of in most districts 

 in Ceylon); so that it would be better to cut them 

 back and make them throw out fibrous roots and 

 so "ive the tree so many more feeders. Jt wus accid- 

 entally found in England that, by cutting back the 

 laroe roots of a fruit tree, it bore better fruit 

 and in larger quantities. No tree ought to have its 

 roots longer than its branches and more especially 

 our coffee, liaoh tree should be kept to itself, so that 

 auy manure put beyond a tree is wasted and misap- 

 plied Forking is sometimes very beneficial. If the 

 soit is stiff and hard, a forking will allow the roots 

 to spread, or, if the roots get too matted, then a good 

 forking will break a lot ot the roois, and so ojien out 



•Oh! dh!— Ed. 



