NOTES AND ABSTRACTS. 



385 



Saxifraga Burserlana and its Varieties. By E. Heinrich {Garden, April 

 11, 1914, p. 179). — The author considers that the form which occurs on the 

 heights round the city of Trient, in the Southern Tyrol (hence tridentina), 

 is S. B. major, while the form found on the Swiss mountains is S. B. minor, the 

 former being of a looser habit of growth and with larger rosettes and flowers. 

 The Swiss form is also distinct in its deeper-coloured flowers and calyces. There 

 is a third form on the mountains of Northern Tyrol intermediate between the 

 two in character. Mr. Negus having stated on p. 143 (March n, 1914) that 

 S. B. gloria does not come true from seed and that his specimen bears two and 

 possibly three flowers on one stem, the author considers that this points to the 

 probability of S. B. gloria being a hybrid, for even twin flowers are extremely 

 rare on either of the species. But for this multiple inflorescence, S. B. gloria 

 might still be considered as selected as a giant variety of the tridentina form, for 

 there are great differences in the size of the flowers in individual plants as they 

 occur in nature. In some the petals are so narrow at the base as to leave open 

 spaces between them, as in 5. granulata, while others have rounded petals 

 often overlapping each other. S. B. minor has generally overlapping petals, 

 and the author has a form with crenated petals. 



Ib. by E. H. J., May 2, 1914, p. 215. — The author distinguishes S. B. major 

 from 5. B. gloria, major being characterized by large sparkling white flowers, 

 the petals having crenated margins and a meadow-sweet fragrance, the 

 plant spreading laterally and not forming tufts, 5. B. crenata being similar 

 but not so good ; gloria, on the other hand, has considerably larger flowers 

 than major, but flimsy in texture and dead white, without the glistening surface 

 of major, while the plant forms a densely-cushioned tuft. In size the 

 flower is only surpassed by magna, also of cushion growth, while S. B. speciosa 

 has the smallest rosettes and is latest to flower. — H. R. D. 



Seaweed for Manure {Jour. Dep. Agr. Vict. Oct. 1914, p. 634). — Seaweed, 

 which is plentiful on some coasts, forms a cheap and valuable manure. 



The composition varies with the variety, but the following may be taken as 

 the approximate analysis : — 



Water ....... 80 per cent. 



Organic matter ..... 10-20 



Nitrogen '3-*73 



Potash ....... "3-i"9 



Phosphoric acid . . . . . *i-"5 



From the above analysis it will be seen that seaweed is comparable as a 

 manure with farmyard manure, being, however, slightly deficient in phosphates. 

 It has the advantage of being free from weed seeds. — C. H. H. 



Silver-lea! Disease, A Contribution to our Knowledge of. By J. Smolak 

 {Ann. Appl. Biol. ii. July 1915, pp. 138-157 ; figs.). — The author has in- 

 vestigated the characters of cells of leaves of plum attacked by the silver-leaf 

 disease, and finds the differences are much more profound than has been 

 suspected and involve the nucleus as well as the separation of the epidermis 

 from the underlying cells. He finds the cells resemble those of galls, and ques- 

 tions the validity of the evidence which has associated Stereum purpureum with 

 the disease as cause and effect. The fungus, he states, has not been observed in 

 the leaves, and he believes some toxin is secreted in or near the cells which are 

 modified, not in a remote region such as the stem. — F. J. C. 



Snails {Queensland Agr. Jour. July 1914, p. 80). — Snails lay their eggs in 

 heaps of dead leaves, and these hatch out in from twenty-five to thirty days. 

 In the State of San Paulo they are captured by hand, and the high-growing plants 

 most subject to attack are surrounded by a rope of tarred piassava. Low-growing 

 plants are sprayed with a 4 per cent, solution of copper sulphate, and pasture 

 lands with a 1 per cent, solution of bay salt. Ducks and crows readily devour 

 them. The glandinas, or carnivorous snails, will devour from fifteen to thirty 

 of the pests a day, and have been successfully introduced into the south of France 

 and into Tunis. — C. H. H. 



Soil Bacteria, Culture Media for Use in the Plate Method of Counting. By 



H. Joel Conn {U.S.A. Agr. Exp. Stn., New York, Tech. Bull. 38, Nov. 1914, 

 PP- I- 34)- — This paper details the various culture media used in the bacteriological 

 analyses of soils. The author recommends two new culture media : the soil 

 extract gelatine (described in previous abstract) and the sodium asparaginate 

 agar. The advantages of the asparaginate agar are that it contains no 



