48o 



THE TROPICAL AGRICULTURIST. 



[January i, 1884. 



It is to be deplored that so little is kuown of the 

 actual predisposing causes which combine to induce 

 attaoliB of parasitic fungi (especially on trees and 

 shrubs). Dri Carpenter, who was President of the 

 Koyal Microscopical Society of London, says: — "The 

 prevalence of ihese blights to any considerable ex- 

 tent seems generally traceable to some seaeonal In- 

 fluences unfavourable to the health}' developemeut of 

 the wheat plant ; but they often make their appear- 

 ance in particular loclities through careless cultiv- 

 ation, or vant of due precaution in the selection of seed." 

 The converse of what I am trying to establish has 

 been noted on several occasions, but one instance is as 

 good as eeveral. Mr. Knight crossed several varieties 

 of wheat, and, in the Philosophical Transactions for 

 1799, page 201, he says " that in the years 1795 

 and 1796, when almost the whole crop of corn in 

 the island was blighted, the varieties thus obtained, 

 and these only, escaped in this neighbourhood, though 

 sown in several dift'erent soila and situations." 

 This one fact in itself speaks volumes. Similarly 

 with the potato disease, those varieties obtained 

 through judicious crossing were generally found to 

 escape its ravages. 



My motive for publishing these ideas in your 

 columns is not so much for the purpose of re-open- 

 ing the well-worn question of "what ails our coffee 

 trees ?" as to lead to the prevention by adopting pro- 

 per precautions, of a similar affection laying its 

 powerful grasp on what will be soon our tlourishing 

 tea industry. Because the cultivation of a plant in 

 large areas exposes it more particularly to the at- 

 tacks of some disease, it is no reason why we should 

 sit idly by, and bewail our fate when the epidemic 

 occurs : it is our duty to endeavour to prevent by 

 every means in our power the advent of such diseas-e. 

 There is nothing easier than the complete and in- 

 stant destruction of laboratory specimens of a parasitic 

 fungus by the aid of many simple chemicals, but the 

 difficulty lies in the application and contact with 

 success over large areas, as we have now on several 

 occasions witnessed, and so our only course is pre- 

 vention. The subject is worthy of consideration, and 

 its thorongh investigation would lead to the know- 

 ledge of much valuable information, and aleo to many 

 side issues of interest and importance. 



And now if you will permit me, I -a ill answer some 

 of the points you adduce in your editorial on this 

 subject. The polymorphism of parasitic fungi has 

 long been known, and dieplajs several .series of 

 phenomena; and my remark th:it Hemihia rastatrix 

 may have been always present must not be read as 

 having been always an enemy to coflec, but that it 

 possessed a host of some kind, and possibly was 

 identical with its present form, but moi'e probably 

 presented a different appearance. 



Next, as to grub : personally I believe that grub 

 will devour any roots whether .louud or diseased as 

 their voracity precludes partiality; and it was acting 

 on this belief that I used the words "let us take 

 grub, adopting the decayed root theory." That they 

 will eat roots that are sound and hfalthy, I am 

 positive of; but that scmi-decaytd roots are just as 

 alluring, I am equally positive of: indeed, where they 

 exist in large quantities, they have little or no option 

 in the matter. 



I had considered the fact of the felling of forest 

 having no intlueuce to speak of with the increase 

 or decrease of the average of rainfall so well estab 

 liehed, that there was no need for me to dwell on 

 the possibility of tlie present abnormal seasona being 

 inferred therefrom. 



Thanking you for so kindly giving me space for 

 the publication of my ideas — but, unfortun.itely, justice 

 to the subject canuut be done iu a few letters to a 



newspaper without the risk of becoming at the same 

 time wearisome to its readers, j-ours faithfully, 



SWADUY. 

 [We quite appreciate the ability wliich this cor- 

 respondent brings to the discussion of a very difficult 

 subject. Granted the polymorphism of fungi in 

 general, and of wheat rust iu particular, all the 

 naturalists agreed that Heniileia rastatrix was new to 

 science and peculiar to coffee. Marshall Ward, in 

 his elaborate reports, never once broached the idea 

 that Hemileia vaatatrix passed from one host to another, 

 changing its forjn in the process? — Ed.] 



THE ALLEGED NEW FIBRE PLANT. 



R. B. Garden, Peradeniya, lOtb Dec. 1883. 

 Sir, — It may save inquiries to slate for the iuform- 

 atiou of your readers that the Conocephalus nivnis 

 mentioned iu the letter from Mr. T. Cliristj- printed in 

 your last issue is the common little' tree known to the 

 Smhalcse as "gasdiM," the tough fibi'e of which is 

 used by them for fishmg lines and similar purposes. 

 It cannot be properly called "a variety of the China 

 grass " to which it has very little resemblauce, though 

 both belong to the great family of nettles, figs and 

 mulberries. The plaut is more generally known as 

 Morvcarpus or Debreyeasia longifolia. — Yours faithfully, 

 HENRY TRIMEN. 



EucALYPTDS IN SpAiN. — In a recent report from Malaga it 

 is stated that the ciUtivation of the Eucalyptus has of late 

 attracted considerable attention in the province of Malaga, 

 which has been deprived of aU but fruit trees, iu order to sup- 

 ply the constant demand for charcoal caused by the extensive 

 use of the fuel for cooking purposes. Large numbers of Euca- 

 lyptus iu a healthy and liourishiug state may now be seen aloug 

 the line of raiiw^ay from Malaga to Bobadilla, and in other 

 places, and they are reported to have been effective, to some 

 extent, in destrojang fevers in the low districts, which were 

 formerly uninhabitable. The Eucalyjrtus trees are also suc- 

 cessfully used for avenues, .and affortl shelter from the sun on 

 the roads near the city. — Gardeners' Clironide. 



Names of ouk Staple Products : Old and New. — 

 Some time ago, Dr. Trimeu was good enough to 

 express himself as follows on a subject which puzzles a 

 good many : — " Cacao and Cocoa. — In my use of these 

 words, I think I have been generally guided by an 

 impression that they refer respectively to the tree 

 ami to its commercial product. The aboriginal name 

 of the plant in Guiana is 'cacao' (but how this may 

 be pronounced I do not know). This native name 

 was adopted (as iu so many other cases) as the bot- 

 anical one, and the spelling retained, and this must 

 always remain, for no one is at liberty to alter 

 what has once been duly published as a scientific 

 name. The failure of tlie attempt to change the 

 name cinchona into ' chinchona ' shows how by com- 

 mori consent botanists resist such action ; it is done 

 in self-defence and to prevent botanical nomenclature 

 becoming a chaos. It is to be regretted that the tree 

 has not been generally called chocolale-lrce. But the 

 jrroducl is another thing. It is always and by every- 

 body called ' cocoa,' and it would be fruitless to at- 

 tempt to alter this. Therefore, it is, perhaps, a little 

 pedantic to spell it ' cacao.' As for the coconut- 

 palm, I think your printing rule of so spelling it 

 practically useful. You will scarcely feel free to 

 adopt the still more phonetic orthography employed 

 on the wrappers of the ' sweet-stuff' sold in Lontlou 

 shops as ' Cokcr-nut Rock.'" We fear it is too late 

 now to settle the difficulty about ' cacao ' and ' cocoa ' 

 by the ado^jtion of the name 'chocolate-tree,' although 

 in talking to strangers we find this term the readiest 

 means of making them understand the nature of the 

 plant ; and among t eylon planters, we fear, not one 

 in twenty unites ' cacao,' while not one in a hundred 

 spruks of the cultivation otherwise than 'cocoa,' 

 Time, howevei-, may correct this. 



