NOTES AND ABSTRACTS. 



315 



Prairie of South Eastern South Dakota. By Le Eoi H. Harvey 

 (Bot. Gaz. vol. xlvi. pp. 277-298 ; October 1908 ; 4 figs.).— Describes the 

 floral aspect of the prairie at different seasons of the year, and points 

 out that it is preglacial in origin, descended from a tertiary prairie 

 which arose in response to reduced rainfall after the Rocky Mountains 

 were upheaved in the late cretaceous period. 



The open xerophytic flora of the crests is gradually invaded, first by 

 " bunch grasses " (tussocks of Andropogon, &c.) and then by sod-formers. 

 Shrub associations of Snowberry and Rhus glabra advance up the 

 northern slopes and prepare the way for the Bur-Oak- Slippery-Elm 

 association which is found in ravines and on flood-plains. 



Trees are absent, and in the author's opinion have never existed 

 upon the true prairie. There is a dry resting season, October to March, 

 and a moist growing season, March to September (with 49-31 cm. of 

 rainfall). 



Though the paper is by no means easy to read, it is to be hoped that 

 English readers may be induced to carry out similar observations in this 

 country. — G. F. S.-E. 



PtePOStyrax hispida (Die dart., p. 357 ; July 24, 1909).— A hand- 

 some shrub with pretty white flowers and large foliage. The time of 

 flowering is during May and June.— G. B. 



Red Oak (Quereus rubra) and the Black Locust (Robinia 

 Pseudacacia) (U.S.A. Dept. Agr., Forest Service, Circ. 58 and 64).— 

 Both these trees, which are of particular value in an economic sense, are 

 well known to us in this country, though the idea of cultivating either 

 for the value of the timber produced has long been abandoned in the 

 British Isles. Certainly the wood of the acacia is particularly lasting 

 when used in connection with the soil, but has never been turned to 

 account in this country. As an ornamental tree the red oak is grown in 

 various parts of Britain, but it is too scarce and of too slow growth to 

 be of value for forest-planting. 



Both papers are full of useful information regarding these two trees. 



A. D. W. 



Red Spider, in Florida, Experiments for the Control of the. 



By H. M. Russell (Jour. Econ. Entom. i. (1908) p. 377). — The red spider 

 (Tetranychus bimaculatus Harv.) proved very destructive during the dry 

 season in Florida. Experiments with the following sprays were tried : 

 lime-sulphur (1 lb. lime, 1 lb. sulphur, 25 gallons water, boiled together), 

 lye-sulphur (1 lb. sulphur, \ lb. lye, 40 gallons water), sulphur (1 oz. to 

 1 gallon water), and kerosene-soap emulsion (1 part of stock solution to 

 10 of water). All of these were found successful in greatly reducing the 

 numbers of red spider and (except the last) were without effect upon the 

 plants. One or two rains do not seriously injure the red spider, but 

 continued rains are fatal to a large proportion. — F. J. C. 



Richardia with Rose-coloured Spathe. By D. Bois (Bev. 

 Hort., August 1, 1909, p. 349). — A hybrid between B. Behmanni and 



