FEBRUARY 8, 1919. ] 
THE GARDENERS’ CHRONICLE 
Chronicle 
FEBRUARY 8, 1919. 
Gardeners 
1676.—8ATU RDAY, 
OONT 
ENT 
67. Potatos, seed 
rmy stable 67 
ám буыла 68 Po - to pits, ventilation 
els Botanic Gardens 67 . 67 
he— | Pritzel, revision of 67 
62 | R. s S. examinations in 
|. 1919 oe ae 66 
69 , Rural cottages from 
} e € 67; Army Hunts . 66 
jarde =: Company, | Snow, = age by 6 
`] onour “or ч of J. 167 | Societie 
E: 541 Бау a Natural History 69 
61 British Carnation .. 68 
Espot "of Orchids 
Devon and Exeter Hort. 69 
West of 
apiid and 
64 
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nal Chrys. ма i] 
Horticultural .. 68 
Winchester Gardeners’ 69 
: Sulphate of copper 
_ Odontioda Norma .. 
_ Odontogloss ossum La Vic- | 
toire da 
gift of a € Ф 
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k beetle Cs 64 
ge constructed from 1 discarded. army d "hut :—Eleva- 
tion, 66; interior, 67 ; 68 
Crocus Imperati . ka Ud s Po 09. 
pressus s funebris, branch of .. Ж» 222 6 
SPOT OF ORCHIDS, 
of Ward Massee— 
olely to ә the. particular section х- 
ned, ж vmm not be Se ruota 
50 
quarter to half E in 
t sunken, bro 
fin show right 
give 
e early stages the 
oe gobak ch 
hire rapidly become dis- 
the ауар le 
lasm 
may A 
condensed water from the cool 
house upon the plants belov 
There is much tru A 
glass roof of the 
in Massee's 
th, 
contention that this particular form of s 
‘does not require the attention of a plant 
pathologist, but the attention of a careful gar 
dene ho has some sense of proportion with 
respect eat E 
The fact that very young leaves are spotte 
equally wi ones, not infrequently 
is 
e that this disease 
И с 
is of an sf eof odis Era and due to the action 
of ано 0 This, however, is not 
the с the eq 
conditions 
cannot spread in | the Since of the. pecifi © 
vironmental factors noted, and it will be equally 
evident that it cannot be prevent 
ру e most scrupulous nli rigorous 
solution. 
ead tissues are rarely more than one quarter 
of ich in sees are re regularl 
circular in form are not so sharply defined 
at ur “periphery. This is the type of leaf 
spot by me, the result of which is 
quote iv . W. in the article already referred 
to. 
Many of the i енд the middle of les 
contain an rphous granular dep 
ch chemically “appear to be not mes he 
ig 
colouring matter indigo. These individual cells 
and all those immediately contiguous are dead, 
but with i ing radial dis the tissues 
become р: ively more merging 
almost im ibly їп Bors functioning 
tion at the periph 
mptoms us 
g- 
Rica this poisoning is the et of so 
e factor; it would seem more probable m 
чы is the effec ^ of "atmospheric ропи io As 
noted by W. W., m 
poat в in collections in or near lar 
well known that many Orchids are 
Жаы a in the 
atm ere of minute quantities of deleterious 
substances. If Me tion be ct o 
would expect cen in 
stomata of the et Né roa the gaseous exchanges 
occur, Lam at present there is no evidence on 
this 
of this trouble it will fes 
епі 
ttention to 
the plant’s health will be of avail, and t 
m this, ps 
—would be the chemical filtration of the 
rh: 
ile Ненов of our а 
cues rth of smoke and chemical fumes 
Orchi see this trouble vanish 
from pde plants. 
керчу types of injury above desc ribed ap- 
common to vi erei all the more 
pear to 
usuall ets species 
A third type of leaf spot, and e of which 
I have had no ex ence, is said by 
Massee to be n у EG 
bidium ebur by the fungus Hypodermium 
Th are 
neum 
orchidearum, Cke. and Mass. e ts 
: Sere often з рэй 
turns Ъ purple, is not rarely seen, 
and this is caused by ies of С} ium, 
may be the C. of Cooke and 
Massee, although morphologically it does not 
appear. to differ from the ubiquitous C. her 
barum, Link. The fungus grows w in pure 
culture, but no actual inoculation experiments 
have been carried out with it. S ho 
ever, take om the tufts of conidio, on 
, diseased leaves and placed A inder the 
raised epidermis healt! s have in every 
i 
case reproduced t pfs ease 
For both of na above dis seases sponging the 
leaves with a dilute cies. of yu sium per- 
manganate has been recommended by Mas 
assee. 
f spot of many species of Orchid is not 
infrequently caused by the fungus Botrytis 
cinerea, Pers., one of the most c on and 
e 
are 
killed outright, but occasionz aliy the parasite is 
bie oe A ын "t ireas: on the leaves, where, as 
of Lilies examined 
by ER W җе mist dps beer lesions 
are uce he great 
н іп pur бы Не pe "ihe se can 
reproduced at will in healthy 
The best general treatme fo otrytis 
disease is 5 ze от the plants with a 
is to sponge or spray t 
to 4 per cent. solution of calcium bisulphate, 
atment might be tried as a tenta- 
i d where 
e 
ve expedient in id houses tl 
fungus is present. It should also be borne in 
that where lass-house is infected wi 
pathogenic fungi the rigo cleanliness 
f the plants and cool diese s ph 
are imperative, as well as 
E d — by Peat of every fragm 
iseased material. After touching diseased 
plant ded hunde should always be washed in 
es of disease have been М 
described 
ose 
ee fes ха term ‘ Orchid 
of circles. On examination the deeply coloured 
Zo; ssue are found to contain empty 
rides tissue 
of a fungus probably belonging to the 
Сана, a group p of ed organisms, which 
ns many t parasitic forms. At 
his f in p cul 
of the rhicwhr Orchid f 
spores and spread rifu i wi eg again 
checked by the Sonam of toxic sub- 
stances. 
This t; disease has been noted on species 
Odontos хе зд Cattleya, robium and 
other undetermine cies, and is probably 
b; the ing of Mage 
Феод 1 » splashing a 
from to leaf, and by the touching o 
iu pid when diseased ones have К 
handled. 
