('akne — Jirown Hot of Citrus. 
phthora (No. 840^ and 7\ tcnu'siris (No. 760) April. 1024. ro- 
eoived from Profossoi’ Fawcett, of the Citrur Fxj)erinKMit Station, 
Kiversido. California, have not only survived room tem])eratures a' 
Perth, but also carried well to London, being forwarded at the samo 
time as P. InbeniaJi.^. ■ . 
Wliile tissues j)laced on agar fruit freely, tliis does nut a}>ply 
to affected fruits, leaves and twigs placed in the moist atmosphere 
in a stop])ered jar, or under a bell-jar. Under such conditions a 
strong short crisj) growth of sterile, myccdium develops on the sur- 
faces. With less liumid conditions l>etter results are sometimes 
obtained. By loosely closing a jar witli, cotton wool, or by e.xposiu'.;' 
to continued rainy conditions in the open spores may sometimes be 
obtained. A fruit forwarded by Afr. Samuel from South Australia 
j)ackel with j)a per in a cardboard box had dev(doped spoi'es on tlu' 
surface when received five days later. When spores are develop'ul 
tliere is no surface growth of mycelium. 
MORPHOLOGY AND DEVELOPMENT. 
The mycelium is at first continuous, much bramdied, very irregular 
in width, and. with swidlings ami knots and short haustoria-like 
branches at irregular intervals. In older cultui’es septa are de- 
veloped scantily (Plate IV). In tissues the mvcelium ajpiears to be 
both inter and intra-cellular, well distributed in leaves, but in fruit 
confined for some time mainly to the skin and i-ag. On agar the 
aerial hyjihae aie twist('d and somewhat irregular, but much less 
so than the submerged mycelium. The average "-idth of tlx* liyphae 
on potato dextrose agar is about -numm. l)ut varies from d to 12mmni.. 
with considerable variation along the same hyphae. Re])ta occui- 
mainly in the older cultures, especially ou subsurface growth. They may 
be straight, but are frequently bent to form a curve or angle or 
have a central tliickening. They commence as ingrowths from tlu* 
op])osite sides of a hypha. The hyjdiae are filled with granular 
protoplasm, but in older cultures fre<pieutly become empty in ])a't 
being cut off by the sei'ta from tlie still active poi-tions. When 
damaged on handling the broken ends of hy])hae readily discharge 
their proto])lasmic contents. On fruity and to a lesser extcuit, leaves 
and twigs kept in a moist jar, and on agar media, the aerial myce- 
lium develo])s as a deiise short Avhite mat of branched hyphae. Tn 
nature during continued wet weather, conidia develop on fruits, 
leaves and twigs. They also develop on aerial and a(iuatic mycelia 
from leaves and twigs, rarely on fruits half submerged iu water, 
and on the aerial mycelium of potato dextrose, prune juice agar, 
and French beau agar. On tissues the sporophores develop singlv 
or in clusters from any portion of tJie surfaces though principally 
from the upper sides of leaves. They are usually clustered develo])- 
