456 
graphs show, also, that much further south, 
at In Salah and beyond, over half way to 
Timbuctu, there is a similar condition of af- 
fairs. It is probable, however, that the vege- 
tation of the mesa-like areas, the reg or the 
hamada, may be barren in the extreme south, 
since even at Ghardaia there is very little 
vegetation on such areas. The mid-Saharan 
country is of the greatest interest botanically 
since there the Mediterranean element is al- 
most wholly lacking, and the influence of the 
countries to the south of the desert begins to 
be felt. We shall await with much expectancy 
the promised detailed account of this remark- 
able journey. 
W. A. Cannon 
DESERT LABORATORY 
BOTANICAL NOTES 
SUPPLEMENT TO ENGLER AND PRANTL’S ALGAE 
THE volume of the “Pflanzenfamilien” con- 
taining the Algae (1., abt. 2) was completed 
fourteen years ago (1897), while most of the 
parts of which it was composed appeared sev- 
eral years earlier. In 1909 two supplemen- 
tary Lieferungen were issued by Wille, in 
1910 two more were issued by Wille, Kjell- 
man and Svedelius, while two more were is- 
sued in 1911 by Svedelius. These have now 
been brought together by the Leipzig pub- 
lisher, Wilhelm Engelmann, under the sub- 
title of “ Nachtraege zum I Teil, 2, Abteil- 
ung.” It covers the period from 1890 to 
1910, and so brings the treatment of the Algae 
down to date. 
The first thing one notices is the consider- 
able modification of the schematic chart of 
the relationship of the families of the green 
algae. The five groups (classes) are de- 
veloped from the Flagellata, the Protococcales 
being the primitive class with Volvocaceae as 
the lowest family. From the latter came the 
Conjugatae as a side line ending blindly. 
Above Volvocaceae are placed Tetrasporaceae 
which lead by one line through Protococcaceae 
to Hydrogastraceae and Valoniaceae, and by 
the other to Ulvaceae. The family Valoni- 
aceae is regarded as the lowest of the class 
SCIENCE 
[N.S. Vou. XXXV. No. 899 
Siphonocladales, which culminates in Dasy- 
cladaceae and Sphaeropleaceae. From Va- 
loniaceae a line reaches Bryopsidaceae in 
Siphonales, culminating in Vawcheriaceae. 
The Ulvaceae are the lowest of the Chaeto- 
phorales, which pass by several lines to 
Chroolepidiaceae, Coleochaetaceae and Oedo- 
goniaceae at the summits of as many genetic 
lines. A significant thing in the treatment of 
these families of green algae is the associa- 
tion of five families of colorless plants as 
“Nebenformen” related to Volvocaceae, 
Pleurococcaceae, Protococcaceae, Oocystaceae, 
and Oedogoniaceae, thus adding another step 
to the movement for the obliteration of the 
distinction between algae and fungi, and 
their assembling into new groups on morpho- 
logical characters. 
In passing it may be noted that Plewrococ- 
caceae are separated from Protococcaceae by 
the absence of zoospores in the former and 
their presence in the latter, contrary to some 
recent algologists. Nor has the author been 
stampeded into dividing Hydrogastraceae 
and in his system Protosiphon and Botry- 
dium lie peacefully side by side as related 
genera in the same family. Characeae are 
still so placed as to immediately follow 
Siphonales, and by this one is reminded of 
Wille’s suggestion of their relationship in 
his earlier treatment. The revision of the 
Phaeophyceae was partly made by Kjellman, 
and on his death it was continued by Svedel- 
ius. It thus happens that some of the fam- 
ilies are the joint work of the two authors, 
while in other cases Svedelius alone did all of 
the work, as in MSphacelariaceae, Lami- 
nariaceae and Fucaceae. The revision of the 
Rhodophyceae also is the work of Svedelius. 
Here the treatment is necessarily the same as 
that of Schmitz and Hauptfleisch fourteen to 
fifteen years earlier. However in the difficult 
family of the Corallinaceae the genera of the 
earlier treatment are freely broken up into 
smaller ones in accordance with the trend of 
recent opinion, resulting in the recognition 
of twenty-four genera instead of nine, with a 
considerable shifting of their places in the 
family. 
