New YorkK AGRICULTURAL EXPERIMENT STATION. 57 
membrane short branches have been produced at the ends of 
which spores are formed. When ripe the spores drop from their 
stalks, and others are formed in their places.” 
THE RUST. 
Carnation rust is distinguished from other rust-colored 
troubles of the leaves by the presence of brown spores, which are 
liberated by the bursting of the “blister” in which they are 
formed. Each spore is normally capable of germinating and 
developing into a fresh spot of rust. Moisture and warmth are 
necessary to the best development of this fungus, hence warm, 
moist houses are more seriously infested than cool, dry ones 
growing the same varieties. Different varieties of carnations are 
subject to the rust in degrees varying with the variety. There 
seems to be some relation between the presence of “‘ bloom ” upon 
the leaves and immunity to the rust, as those varieties which 
have the most bloom are among those which rust but little. ‘The 
rust usually does little real injury to the plant but in severe 
cases it may seriously check the natural growth of the host. 
Once infested the plant continues to be rusted until destroyed. 
The hyphe of the fungus penetrate the leaf and stem-tissue and 
‘produce here and there the pustules of spores, which are the visi- 
ble evidence of the rust plant. Cuttings taken from a rustéd 
parent produce rusted plants’, indicating the presence of the fun- 
gus hyphe in the actively growing portions of the plant. When 
the rust spores germinate they gain access to the interior of the 
leaf either through a stomate or some weak or broken spot in 
the leaf. From such a point as center the disease spreads 
through the cells of the host, securing the needed nourishment 
from these cells. It is now safe from any external treatment; any 
checks to its further development must be able to reach it within 
the tissues of the host and yet do no material injury to that host. 
Such a check is the fungus Darluca filum. 
2Sapin-Trouffy in Le Botaniste, 5: 51. 
®Statement made by carnation growers of experience, 
