NOTES AND ABSTEACTS. 



391 



The botanical cHaracteristics, life histories, and physiological 

 specialization of parasitic fungi vary with the geographical distribution, 

 and investigations on rusts by European botanists cannot be accepted 

 as final in America. The rusts are divided into stem and leaf rusts, 

 the stem rusts being of the most importance economically; some of 

 the leaf rusts do not cause much damage. 



The distribution of rusts in the United States is carefully worked 

 out. In districts where the annual rainfall is below twenty inches the 

 rusts are generally of little importance. Spraying experiments and 

 soil treatment for the prevention and control of rust proved to be 

 useless from a practical point of view. 



In 1907 and onwards the authors undertook extensive continuous 

 cultural experiments to determine the vitality of successive Uredo 

 generations of various grain rusts. Summaries of the results are given 

 in a number of tables, and the experiments showed that for fifty -two 

 generations there was no apparent diminution of vitality. 



All the recent work on the breeding of immune varieties is sum- 

 marized, and a comprehensive bibliography given at the end of the 

 Bulletin.— D. M. C. 



Salvinia, Development of. By Sigismund Zawilski {Beih. 

 Bot. Cent. Bd. 28, Abt. i. Heft 1, pp. 17-65; 91 figs.).— This paper 

 gives a complete description of the whole anatomy and development 

 of Salvinia, and is very fully illustrated. — G. F. S. E. 



Sap Stain in Lumber, The Prevention of. By Howard F. 

 Weiss and Charles T. Barnum (U.S.A. Dep. Agr., Forest Service, 

 Giro. 192; Nov. 23, 1911). — Experiments on a large scale have been 

 conducted" in the United States as to the cause and prevention of sap 

 stain in timber. 



The nine conclusions arrived at are most valuable to the wood 

 merchant, the best results having followed the use of mercuric 

 chloride solutions when applied to the timber soon after felling. 



A.D.W. 



Saxifraga ling-ulata (Bot. Mag. t. 8434).— Maritime Alps. 

 '^Q.milY Saxifragaceae ; tribe Saxifrageae. Herb, with a rosulate crown 

 and a central flowering stem. Leaves linear, 1-5 inches long, red 



^ near the base and with numerous marginal pits loaded with chalk ; 



i peduncle- many-flowered ; flowering stem 2-5 inches long; flower 1^ 



! inch across; petals white. — G. H. 



I 



I Schomburgkia Lueddemani (Bat. Mag. t. 8427). — ^Venezuela. 

 . Family Orchidacme ; tribe Epidlendreae. Herb; epiphytic. Pseudo- 

 j bulbs 6-10 inches long; leaves 8-14 inches long; scape 1^-2 feet long; 

 i flowers 3 inches across from tips of sepals; sepals and petals -J inch 

 1 broad, brown with purple lip and column. — G. H. 



Scrub Pine. By W. D. Sterrett (U.S.A. Dep. Agr., Forest Ser- 

 j vioe. Bull. 94; July 22, 1911). — Botanically known as Pinus virginiana, 



