270 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



that at Linden Towers there are numerous specimens of Araucaria 

 of four species, including three individuals of A. brasiliensis, which 

 last are about thirty years old and 25 to 60 feet in height. The largest 

 is about 20 inches in diameter. 



One terminal bud may produce 1000 spore leaves, each with 

 10-15 sporangia bearing 500-1000 pollen grains, so that there may be 

 a billion pollen grains. 



The author finds the dehiscence structures very like those of ferns. 



The sperm cells are very large (150 fx or more in length) and possibly 

 motile. 



The evidence " goes far towards inducing a belief in the primitive 

 condition of the Araucarians." — G. F. S. E. 



Arsenite of Zinc and Lead Chromate as Remedies against the 

 Colorado Potato Beetle. By F. A. Johnston (U.S.A. Dep. Agr., Bur. 

 of Entom., Bull. 109 ; April, 1912). — The best results were obtained 

 by using 2 lb. arsenite of zinc to 50 gallons of water. Lead chromate, 

 which settles far more rapidly than the zinc chloride, gave much 

 less satisfactory results (1 oz. to 1 gallon of water was used). — F. J. C. 



Arundo tenax, To Make Seed Pots of. By Dr. G. V. Perez (Jour. 

 Soc. Nat. Hort. Fr., 4th Series, vol. xiii., p. 717, Nov. 1912). — A note 

 on the use of lengths of the stems of A. tenax, in place of earthen- 

 ware pots, for seedlings and cuttings. The lengths may vary in size 

 according to the use to which they are to be put, and the writer contends 

 that they take up no room, are less easily broken, and the transported 

 contents suffer much less than when ordinary pots are used. — M. L. H. 



Azalea indiea, ' Mme. Jean Haereus.' By L. de Nobele (Rev. Hort. 

 Beige, No. 4, p. 57, Feb. 15, 1912 ; plate). — This variety of A. indica, 

 first shown at Charleroi in 1907, is said to be magnificent in colour and 

 size, and to possess every quality which can be desired in a commercial 

 or amateur's Azalea. It lasts long in bloom, is hardy, easily reproduced, 

 and the petals are not at all inclined to drop. — M. L. H. 



Bog Plants. By Alfred Dachnowski (Bot. Gaz., pp. 503-514 ; 

 Dec. 1912). — The author discusses the various possible causes which 

 may limit the development of ordinary plants in peat bogs. 



Evaporation in a bog-forest averaged 8*1 c.c. daily, and corresponds 

 to that found in a beech maple forest. In a bog meadow it was less 

 (10-9 c.c.) than that found in an open field (15-8 c.c). Neither sub- 

 stratum temperature nor difference between air and soil temperature 

 can act as selective factor for the plants able to grow in bogs. Osmotic 

 pressure is very nearly alike in the various plant zones in a bog, and 

 is much the same as found in lake and river water. Nor does variation 

 in the position of the water table influence the vegetation. In poorly 

 decomposed bog-meadow peat the percentage of volatile matter is 

 high, whilst that at fixed carbon, nitrogen ash, is low (the reverse is 



