130. Harris: THE TisSUE FLUIDS OF CUSCUTA 
The explanation of these results, which are conspicuously dif- 
ferent from those elsewhere announced for the Loranthaceae, and 
from others which are still unpublished for root parasites, is not 
clear. It must be the object of further investigation. Possibly 
the hydration of colloids plays a part in the phenomenon. Pos- 
sibly the Cuscuta is highly ephemeral in its development and 
grows only at a time when water lost from the host to the parasite 
can be readily replaced by the host plant from the soil. 
In this connection it is interesting to note that the Allenrolfea 
upon which these plants of Cuscuta were found grew in a locality 
where a number of other plant species occurred, and not under the 
most saline conditions of the areas along the southern shore of the 
Great Salt Lake (3), (6). 
SUMMARY 
Determinations on Cuscuta indicate that the desert forms 
have a far higher osmotic concentration of their leaf tissue fluids 
than those of moist regions. This result is in accordance with the 
findings so far published for the osmotic concentration of the 
mistletoes. : 
When parasitic on an extreme halophyte, Allenrolfea occiden- 
talis, the dodder, Cuscuta salina, shows high values of osmotic 
concentration, specific electrical conductivity and chloride con- 
tent, but these are in every instance lower than those demon- 
strated in the tissue fluids of the host plant. This result is con- 
trary to that generally found for the Loranthaceae. 
Dynamic phases of these interrelationships are open to 
investigation. 
LITERATURE CITED 
(1) Harris, J. Arthur. oor 
1918. On the osmotic concentration of the tissue fluids of 
desert Loranthaceae. Mem. Torrey Bot. Club 17: 
307-315. 
2), 
1918. Secondary parasitism in Phoradendron. Bot. 
Gaz. 66: 275-276. 
