1906] BERGEN—LITTORAL SPERMATOPHYTES 331 
In order to avoid the possible presence of traces of salts of copper or 
other injurious metals sometimes found in distilled water the solu- 
tions were made up with very pure cistern water. 
Much difficulty was experienced in getting perfectly comparable 
results from the fact that slight individual differences in the plants 
(such as relative development of the root system) made decided 
differences in their tolerance of the saline solutions employed. Many 
values were discarded, from the fact that they were evidently errone- 
ous from variations of this kind. In general, as was to be expected, 
the duration of life in sea water was considerably greater than in a 
pure sodium chlorid solution containing the same per cent. of this 
salt (2.88) that is found in Mediterranean sea water. Some of the 
principal results obtained are summarized in the following table: 
ORDER OF RESISTANCE TO SALINE SOLUTIONS. 
2.88 percent.| In 100 per cent. 
pet NaC], sea water, 
lived days lived days 
Euphorbia — ee eee eee 17 20 
PAOGES GEIS 6 305 os peewee oes eS 19 
Euphorbia Actinic? ee ree eee ere 2-13 9 
Echinophora eee Gi bcd, RRR OE eV Pe 7 
Polygonum maritimum........5.....+:+- g-I0 
Alyssum maritimum (ioral Peay ee 7 
cx Plan cantar 7 
Senecio vulgaris (itoral). EF re . 5 
Sage eae oe . 
It is noteworthy that the littoral and the inland specimens of 
Alyssum and of Senecio were equal in their resisting power, as might 
have been expected from the comparatively equal amounts of chlorid 
in the beach sand and the vineyard soil. 
Some experiments were made to ascertain the maximum per cent. 
of seawater which could be tolerated by the species of Association A 
without speedy appearance of symptoms of injury, such as partial 
drying up or death of shoots. Difficulty was found in discriminating 
between retardation of growth and weakening caused by culture 
under artificial conditions, and that due solely to the excessive salinity 
of the culture solutions. It was considered that a plant was unharmed 
if it showed no decided ill effects from the solution (except retarded 
