NOTES AND ABSTRACTS. 



511 



grown under normal conditions, and this special power may become 

 a permanent inheritable character. 



Different varieties respond in different ways to new conditions, and 

 the variants of one variety " depart in both directions from the 

 normal." 



The author thinks that it is by this power of resistance, by dimi- 

 nishing the rate of absorption, compared with transpiration, in the pre- 

 sence of poisonous products that plants succeed in establishing them- 

 selves in physiologically arid habitats, such as peat. 



They are not so much assisted by developing xerophytic characters. 

 Neither the low temperatures in peat mosses nor differences in acidity 

 and osmotic pressure have much effect. — G. F, S.-E. 



Philadelphus 'Mer de Glace.' By Hort. (Le Jard., vol. xxiii., 

 No. 542, p, 277; Sept. 20, 1909; 1 fig.).— A new hybrid, differing from 

 PliiladelphiLS Lemoinei by its large leaves and fine flowers. It has a 

 very regular habit of growth. The branches, which bloom profusely, 

 are short and erect. They bear a quantity of double rose-like flowers, 

 with very large outside petals and narrower petals inside, of a fine 

 silvery white. — F. A. W. 



Pine Sawyer, The Southern (Monohammus titillator Fab.). 

 By J. L. Webb, M.S. {U.S.A. Dep. Agr., Bur. Entom., Bull. 58, 

 part iv. ; Nov. 10, 1909 ; 24 figs, bibliography). — This insect, as far 

 as is at present known, attacks only felled or injured pine trees. 



The adult female is a long, mottled gray and brown beetle, varying 

 from 16 mm. to Bl'5 mm. in length, and from 5 mm. to 10 mm. in 

 width. She digs a funnel-shaped pit in the bark of the tree, prepara- 

 tory to laying her eggs. As many as nine eggs have been found in one 

 pit. 



In about fivje days the larvse hatch out and commence feeding on 

 the soft inner bark, and soon work their way through it. Eighteen 

 to thirty-two days after hatching they mine into the sap-wood, making 

 tunnels or galleries till the heartwood is reached. The pupal period 

 is passed in a cell in one of these galleries, the adult beetle emerging 

 by boring a perfectly round exit hole three-eighths of an inch in 

 diameter. 



The beetle has several natural enemies, but they are not powerful 

 enough to be of much service. At Baxterville, Miss., in 1908, the 

 felled timber was burned over with the object of destroying broods of 

 larvae, but very few of them succumbed to the heat. 



The author recommends that all storm-felled trees should be sawn 

 into logs and placed in water before the larvae enter the wood, or 

 within forty days after the eggs are laid. If it is impossible to place 

 the logs in water they should be barked within forty days after the first 

 egg-pits are discovered.— F. G. J. 



Plant Associations of the Sudetic Alps. By Prof. Laus 

 {Beih. Bot. Cent. xxvi. 2. Abt. Heft i. pp. 103-131; 1909).— The author 



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