180 
(2.) If the stem of a plant that has been diseased at the roo; for some 
time is examined, very minute black lumps just visible to the naked eye 
e seen scattered over the surface, and, in addition, small black, 
produces myriads of conidia or very minute reproductive bodies which 
are dispersed by wind and inoculate other plants. By this method 
disease ELT diffusion of the c 
As conidia are dispersed ped by very low, earth currents of air, 
sereens of branches might with renee be erected between the 
plantation and the infected forest regio 
The benefit derived from the fires ua which allusion is made is ex- 
Sidi by the fact that each fire forms a v c: through which a certain 
volume of spore-laden air passes, and is pur 
When the root form of the disease has Rei itself, it is useless to 
plant again on the same spot before the soil has been thoroughly 
sterilized ; lime, if available will effect this; wood ashes is also good for 
“s pp 
: y, great care should be taken in the selection of perfectly healthy 
iR. aus -frée) portions of the plant for purposes of propagation. 
. - 
No portion of any plant showing kA disease at any E should be used, 
for although portions of such plants may present no external indica- 
tions of disease, yet, in all beobability, the fisted of every portion 
contain mycelium which at a later stage will grow out and show the 
disease. In many parallel cases, where root dad" is the trouble, the 
bee is in reality fostered by the antag of diseased cuttings. 
M: 
CCCCLXIX.—DECADES KEW ENSES. 
PLANTARUM Novarum IN HERBARIO Homri REGII CONSERVATAKUM. 
DECADES XX. & XXI. 
With a few exceptions, the plants of the two folowing y apes are 
from the collection made by Mr. J. Theodor 
e Bent on his 
journey in Arabia Felix. Some particulars of the usato will be 
found at p. 158. 
191. Ionidium durum, Baker [ Violacezx] ; sonroseoaee ramulis 
. lignosis albidis junioribus pubescentibus, foliis ad nodos iculatis 
A integris vel obscure erenatis basi cu ins sessilibus vel sub- 
ibus firmulis margine recurvatis utrinque viridibus obscure 
pubescentibus stipulis deltoideis albidis blandis persistentibus, floribus 
: solitariis breviter pedicellatis, ps ovatis viridibus albo- 
= marginatis petalis albis calyce 4-6 plo longior 
z ee —South-east Arabia: Dhofar Mountains at 2000 T J. T. 
