1918] WEIR—RAZOUMOFSKYA 3 
accumulating, but this seemed desirable in case all necessary notes 
were not taken on both generations. In the case of continuing 
the inoculations of the same species of mistletoe through several 
generations on the same host but different individuals, either in the 
same or different localities, or on different host species, the saving 
of specimens fully recorded is doubly necessary. This should also 
furnish some information on the subject of the germinal transmission 
of characters. 
Cultures begun in 1914 are being conducted both in the field 
and in the greenhouse. This doubles the amount of work, insuring 
greater dependency on results; and in the case of the indoor work 
closer study is possible of the life history of a successful inoculation. 
Indoor work also permits the use of a larger number of trial host 
species. The seeds germinate more rapidly and results are sooner 
obtained. One of the chief reasons for maintaining outdoor cul- 
tures is to check, whenever possible, under natural conditions, 
any unusual result obtained in the greenhouse. Cultures in the 
open have so far proved more successful than those inside, where 
the same mistletoes and hosts were concerned. If, however, a few 
unusual hosts are obtained indoors, it must be remembered that 
it is a new association of host and parasite often not possible 
in nature; moreover, some of the mistletoes showing the greatest 
predilection for a particular host or host genus are Cece eee 
found on trees belonging to other genera. 
In making the inoculations great care is exercised to attach the 
seeds at the most vulnerable points, such as in the axils of the leaf 
sheaths, tender branches, base of terminal buds, and in the denser 
zone of needles at the nodes. Observations show that infection 
usually occurs at these places.‘ Before the seeds are transferred 
to the host they are allowed to stand for a few minutes in water. 
This causes the mucilaginous coat of the seed to expand. The 
seeds are then sucked against the point of a dropping pipette and 
placed firmly in the desired position. After a short time the 
mucilaginous layer dries, holding the point of the seed in place. 
The host material used in the inoculations ranges from seedlings 
2 years old to the tender branches of mature forest trees. In case 
* WEIR, James R., Wallrothiella Arceuthobii. Jour. Agric. Research 4:377- tots. 
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