2oS BOTANICAL GAZETTE [march 



African fresh-water algae. — The fresh-water algae collected by the third 

 Tanganyika Expedition (1904-5), under Dr. W. A. Citnningtox, have been 

 reported by G. S. West.^5 The collections were extensive and consisted lai^ely 

 of plankton obtained from the three great lakes (Nyasa, Victoria Nyanza, and 

 Tanganpka). Some material was collected in swamps and swampy pools, and 

 some of the most interesting algae were obtained from among the finely divided 

 leaves of certain utricularias. The ph}toplankton is first presented, and is peculiar 

 in the absence of many genera which are a dominant feature of the European lake 

 plankton. A table shows all the species observed in these African plankton col- 

 lections, and this is followed by a discussion of the peculiarities of the plankton 

 of each lake. The bulk of the report consists of the systematic account of the 

 algae. The absence of Stigonemaceae is referred to as remarkable, Nostochopsis 

 being the only representative of the family. Species of Hapalosiphon are of gen- 

 eral occurrence in swamps and marshes, as well as certain bog-loving and rupestral 

 species of Stigonema. The list of new forms includes 18 varieties, 36 species, and 

 a new genus (Sphinctosiphon) of PalmeUaceae. The total number of species is 

 372 (105 genera), and 122 of the 187 Chlorophyceae are Conjugales. 



Certain conclusions are as follows: The algal flora of Tanganyika differs 

 very much from that of the other lakes, but its peculiarities could be accounted 

 for by prolonged isolation. The algae of Tanganyika showing marine affinities 

 may have been produced by a gradual increase m the salinity of the water over an 

 extended period. The relatively small proportion of Chlorophyceae in the plank- 

 ton, as well as the large proportion of Bacillarieae and Myxophyceae (Cyanophy- 

 ceae), is also an indication that the water of the lake was at one time more saline. 

 In large bodies of fresh water, a single example of plankton from a given locality 

 must not be regarded as representative of the plankton of the entire lake.— J. M. C- 

 Califomia p»ch blight. — ^Ralph E. Smith describes this disease as occurring 

 m practically ever}' part of California where peaches grow J^ It was first recorded 

 in 1900 by Pierce and has since increased largely. All varieties are affected. The 

 buds and fruiting twigs die, the green twigs become spotted, and the leaves and 

 fruit drop off. Gum exudes copiously, especially in wet weather, over the one- 

 year-old fruiting tmgs. Twigs which were sound and tealthy in December were 

 found to be spotted by the first of Februar>% Spraying with Bordeaux mLxtuie 

 at the usual time was not effective, but spraying in December proved efficient, 

 and the ordinary Bordeaux of the 5-5-50 strength of the lime-sulfur-salt mixture 

 is recommended. 



The fungus is referred to Coryneim beyerinkii. The mycelium produces spots 

 on the leaves and shoots in winter and spore pusttdes near the center of these 

 spots. Affected leaf tissue soon drops out, ^ving rise to '^shot-holes." Conidia 



15 West, G. S., Report on the fresh-water algae, including phytoplankton, of the 

 third Tanganyika Expedition conducted by Dr. W. A. Cunmngton, 1Q04-5. Jo^- 



1907 



16 



Agr. Exper. Sta. Calif., BulL 191. Sept 



