1915] CURRENT LITERATURE 327 
Ten years ago, in a paper on alternation of generations in animals,’ 
the reviewer predicted that gametophytes more reduced than those known at 
that time might still be found. Miss Pace soon described the Cypripedium 
type and afterward various investigators found digressions from the ‘‘normal”’ 
type in Peperomia, Penaea, Oenothera, Clintonia, Lawia, Podostemon, Dicraea, 
Helosis, and Plumbagella. 
It is interesting to note that the most reduced sac has not been found in the 
most advanced family. It has been a prevalent custom for investigators to 
focus their attention upon forms which at the moment seemed to have particu- 
lar phylogenetic significance, forgeteng not ed that Phylogenetic. echemnes 
might be awry, but also that facts of g 
might be found in plants not in the supposed line of ascent. a, 7 " CHAM- 
BERLAIN. 
Phytopathology in the tropics——Dr. JOHANNA WESTERDIJK presented a 
paper at the twenty-fifth anniversary celebration of the Missouri Botanical 
Garden dealing with the general facts concerning plant diseases in the tropics, 
ased upon recent observations she had made in the Dutch colonies of the East 
Indies. e combination of high temperature and moisture would seem to 
be peculiarly favorable to fungi, and therefore to diseases of economic plants 
induced by fungi; but in fact there are only a few such diseases of real impor-* 
tance. Not only among cultivated plants, but also among the native plants 
are attacks of fungi rare. Dr. WESTERDIJK has concluded that the tropical 
temperature is too high for many fungi, a conclusion confirmed also by experi- 
mental work. The condition of the tropical host is also unfavorable for 
invasion by fungi because of the high water content and small air content of 
the tissues concerned. Among the disease-producing fungi in the tropics, 
mention is made of the root fungi (certain Hymenomycetes) which attack 
practically all cultural woody plants. The fungi (certain Ascomycetes and 
Fungi Imperfecti) inducing die-back diseases of orchards and forests, so com- 
mon in temperate regions, are represented in the tropics only by a Corticium 
(a Hymenomycete); and there are no representatives of the powdery mildews 
(Erysiphaceae). The relation of fungus attacks to temperature is well shown 
in the behavior of Phytophthora infestans in Java, where potatoes are culti- 
vated in mountain districts between 1500 and 6000 feet altitude. In the lower 
areas the infected regions are rare, but in ascending to the higher areas of lower 
temperature, the more destructive does Phytophthora become. Among the 
rusts there is only one representative of importance in tropical agriculture, 
namely the coffee leaf disease (Hemileia vastatrix). Leaf spot diseases are 
much less frequent than in Europe or in the United States; while bacterial 
8 Bor. GAZ. 39:137-144. 1905. 
9 WESTE or — Phytopathology in the tropics. Annals Mo. Bot. 
Gard. 2:307-313. 
