NOTES AND ABSTRACTS. 



617 



Agricultural Production in the United Kingdom, Economic 

 Conditions Of. By Albert Dulac {Ann. Agr. vol. xxviii., Nos. 3 & 8, March 

 and August 1902). — An excellent essay dealing with the incidence of 

 imperial and local taxation on agriculture, rent, social conditions, soil, 

 climate, crop and animal production, cost of production. — C. H. H. 



Ajugas. By S. Arnott (Gard. Mag. No. 2597, p. 528; 8/8/03).— 

 The modest little genus Ajuga numbers a few beautiful border plants. 

 Several species and varieties are described in this article, which is 

 illustrated by the pretty A. Brockbanki, one of the best varieties. — W. G. 



Albinism in Maize. By B. D. Halstead (U.S.A. Exp. Stn. Neiv 

 Jersey, Bejp. 1902, pp. 409-412 ; plate). — Experiments to show the 

 influence on the production of albino seedlings of the amount of 

 moisture given during germination, and of the source of seed, whether 

 from ill-developed ears, from albino ears, twin ears on a stalk, or from 

 inbred or wide-bred corn. The experiments, which were not sufficiently 

 extensive to yield reliable results, point to close fertilisation as a cause, 

 and it is recommended that plants from which it is intended to save seed 

 should have male inflorescences removed. — F. J. C. 



Algae, Remarks on the Periodical Development of, in the 

 Artificial Waters at Kew. Note by F. E. Fritsch (Ann. Bot. vol. xvii. 

 No. lxv. p. 274 ; January 1903). — All who are concerned with fresh- 

 water Algse must be interested in this paper. 



" Whilst working out the algal flora of the Royal Botanic Gardens at 

 Kew for publication by the authorities, I have made several observations 

 on the periodicity of the flora which I wish to remark upon more fully 

 here. The flora was found to be built up of a hot-house element, con- 

 sisting for the greater part of Cyanopliycece ; of the Thames element due 

 to the universal use of river-water throughout the gardens ; and lastly of 

 the open-air terrestrial element." 



In a footnote we are informed that " a large number of the blue-green 

 Algce, which occur in the moist heat of greenhouses, have also been 

 observed in hot springs of different parts of Europe, notably those of 

 Carlsbad ; this seems to show that they are not truly indigenous in 

 Europe, but can only exist under the peculiar conditions (i.e. high tempera- 

 ture and moisture) found at these particular spots. . . . The hot -house 

 flora is practically equally developed during the whole year, the conditions 

 under which it exists remaining uniform. The flora outside, however, 

 shows quite a different character in the winter and in the summer, and 

 attains its maximum development in August and September. ... In all 

 the artificial waters at Kew a regular sequence of forms was observed ; it 

 was most pronounced in the Aquatics' tank near the Jodrell Laboratory, 

 in which, by the removal every now and then of the mass of Algte that 

 collects there, room is constantly being furnished for the development of 

 other forms. . . . Oscillaria nigra also played an important part in the 

 Water-Lily pond. In the earlier part of the year a Cladophora was the 

 most abundant here, and no trace of Oscillaria was to be found. During 

 the summer months the latter genus, however, attained an enormous 

 development, the whole bottom of the pond being covered with a thin 



x 



