Harris: THE TissuE FLuips or Cuscuta 129 
In 1920 while working in cooperation with R. A. Gortner, W. 
F. Hoffman and A. T. Valentine in Tooele Valley, Utah, the 
writer found Cuscuta salina Engelm. on the extremely halophytic 
Allenrolfea occidentalis (S. Wats.) Kuntze. The determinations 
in the accompanying table were made on tissues of the parasite 
collected from many host plants and on the samples of tissue of 
the individual host plants upon which the parasites were growing. 
The results appear in the accompanying table. 
Number Freezing | Osmotic Specific |Ratioofcon-| Chloride 
and point pressure in | electrical |ductivity to| content 
Species depression | atmospheres |conductivity) depression | per liter 
P K K/A Cl 
C 20723 
Cuscuta 2.25 27.0 .0205 . OOgI ne 
Allenrolfea 3.70 44.4 .0700 . 0186 21.8 
Difference | —1.45 —I17.4 —.0495 — .0095 —16.5 
C 20727 
Cuscuta 216 26.0 . 0183 . 0085 3.8 
earn 3.56 42.6 .0690 . 0194 19.1 
Biller —I.40 —16.6 — .0507 —.0109 —I15.3 
C 20729 
Cuscuta 2.07 24.8 . 0203 - .0098 4.5 
Allenrolfea 3.21 38.5 . 0652 .0203 £72 
Difference | —1.14 —I13.7 ——.0449 —.0105 | -—I12.7 
In each of the three pairs of determinations the osmotic con- 
ayrebnions as oe in terms = freezing point depression, 4, 
anda m ti , is lower in the Jadeate 
than in the host. Thesame is true of the specific electrical con- 
ductivity, K, and of the ratio of specific electrical conductivity to 
freezing point depression, K//\. Thus the concentration of total 
_ solutes and of solutes capable of carrying the electric current is 
lower in the parasite than in the host plant. 
The determinations on chloride content made by Mr. Law- 
rence by a method described elsewhere (7) are particularly inter- 
esting. The results are given in terms of grams of Cl per liter of 
tissue fluid. The tissue fluids of Cuscuta contain only about one- 
fourth of the chlorides found in the host plant. 
