NOTES AND ABSTRACTS. 



751 



plants are thus a wide selection, yet the general effect of environment 

 in each case is much the same. We translate the more important 

 effects of growth in dry air ; as a rule moist air gives the converse, 

 while normal growth is intermediate. A dry atmosphere : — restricts 

 growth in height, and increases the rigidity of stems ; diminishes the 

 length of internodes, but increases the number ; reduces the size of the 

 blade, petiole, and stipular region of the leaf ; increases the thickness 

 of the leaf and deepens the colour, the palisade tissue being deeper while 

 the spongy tissue is reduced ; promotes greater development of hair 

 structures and stoniata ; increases the development of the root, and in the 

 Leguminosce tends to retard the growth of root-tubercles ; hastens 

 flowering and fruit ; augments glands and nectaries in plants which have 

 them ; diminishes the diameter of epidermal cells ; reduces cortex and 

 pith, but promotes the differentiation of sclerenchyma and cork, and 

 causes a greater development of wood ; favours the production of 

 secretory canals and secretions, including raphides. — W. G. S. 



Avocado in Florida. By P. H. Rolfs (U.S.A. Dep. Agr. Bur. PI. 

 bid., Bull. 61, 1904 ; 4 plates and 9 figs.). — The Avocado or 

 Alligator Pear (Persea gratissima, Gaertn.) has not been very extensively 

 cultivated in Florida, the chief supply up to the present time having come 

 to the United States from the West Indies. This bulletin suggests that 

 it is a salad fruit worthy of improvement and cultivation in Florida, Porto 

 Rico, Hawaii, and those districts of California which are free from frost. 

 The methods of propagation and cultivation are detailed. The trees are 

 best budded or grafted, as they do not come true from seed. Instructions 

 as to picking, grading, and packing the fruit, and a description of some of 

 the chief variations, are given. An ideal fruit weighs about 1 lb. to 

 1| lb., is Pear-shaped or oblong, has the seed closely surrounded by flesh, 

 and is either yellow or scarlet in colour. The fruit is eaten raw with or 

 without various condiments, or may be pickled. Spraying with Bordeaux 

 mixture keeps the commonest fungal disease, caused by a species of 

 Glceosporium, in check. — F. J. C. 



Bacteria of the Soil (U.S.A. Exp. Stn. Kansas, Bull. 117, 

 5/1908; 3 figs.). — Notes are given on bacteria in general, and on the 

 ways in which bacteria may be cultivated. Tables follow showing the 

 variation in numbers of bacteria found in soil at varying depths, in 

 different localities, and under different treatment. — F. J. C. 



Bamboos, Himalayan. By 0. Stapf (Gard. Chron. No. 907, 

 p. 805 ; No. 908, p. 825 ; No. 909, p. 340 ; No. 910, p. 356 ; May 14, 

 21, 28, June 4, 1904). — The author in this paper gives a full account of 

 the history, introduction into Europe, the habitat, &c. of two species of 

 Bamboos, Arimdinaria Falconer i and A.falcata, and says: "Nevertheless, 

 there is still considerable confusion concerning these .two species, and it 

 has become more complicated by the accession of A. nobilis, a new 

 species proposed by the author of 'The Bamboo Garden,' and by the 

 doubtful position of the A', gracilis of the horticulturists. An account of 

 their history and distinctive characters may not be out of place." 



, G.S.S. 



