574 Floristik u. Systematik der Phanerogamen. — Agricultur etc. 



contains the following illustrations: 32. The mountain forest of 

 Yumoto (Nikko) in autumn; 33. Forest scenery at Yumoto, 

 Nikko; 34. and 35. Tsuga diversifolia Maxim.; 36. Inside of the 

 Tsuga forest at Yumoto, Nikko; 37. Thnjopsis dolobrata Sieh, et 

 Zucc; 38. Larix leptolepis Card.; 39. Betula alba L. var. vulgaris 

 Regel.; 40. Forest Vegetation at the Water-fall Yudaki, Nikko. 



In Set VI. the following illustrations are given : 41. Pinus 

 luchuensis Mayr; 42. Bischoffia javanica Bl.; 43. View of a village 

 Street with groups of cultivated plants ; 44. and 45. Cyathea spinu- 

 losa Wall., 46. Bruguiera gymnorrliiza Lam. Miyoshi. 



RvDBERG, P. A., Flora of Colorado. (Bulletin 100, Agricultural 

 Experiment Station of the Colorado Agricultural College. Fort 

 Collins. Col. 1906.) 



A locality list, with füll keys, of the Pteridopliytes (40) and 

 Spermalophytes (l'&ll species) of Colorado, a number believed 

 by the author to be surpassed only by the flora of California 

 and perhaps Florida, among the States of the Union. Of this 

 total, the Compositae comprise 568 (about VO» and the grasses 267 

 (about Vio)- The book, which is a thick octavo, with map, bears 

 evidence of careful work; and although descriptions are limited to 

 the terse lines of the keys, it should prove indispensable to those 

 studying the plants of Colorado. Trelease. 



Selland, S. K., Floristiske Undersögelser i Hardanger. 1. 

 (Bergens Mus. Aarb. 1906. No. 5. Bergen 1906. p. 1 — 17.) 



Spezielle Lokalitäten für floristisch wichtige Phanerogamen am 

 inneren Hardanger Fjord, Norwegen. 



Jens Holmboe (Bergen). 



Selland, S. K., Om Vegetationen paa Voss og Vosse- 

 stranden. (Nyt Mag. f. Naturw. Bd. XLIV. Christiania 1906. 

 p. 159 flg. Mit einer Karte.) 



Sehr sorgfältiges Verzeichnis der im Gebiet (östlich von Bergen) 

 vorkommenden Gefässpflanzen. Jens Holmboe (Bergen). 



Hall, A. D. and A. Amos, The Determination of available 

 Plant food in soil by the use ofweakacid Solvent s. 

 Part II. (Transactions of the Chemical Society. Vol. LXXXIX. 

 p. 205—222. 1906.) 



A weak acid solvent is usually employed now to determine the 

 „available" universal plant food, particularly phosphoric acid and 

 potash, in soils. A one per cent. Solution of citric acid, as first 

 suggested by D y e r , is the solvent generally adopted, although 

 American Chemists prefer a N/200 Solution of hydrochloric acid. 



The authors point out that there is an objection to regarding the 

 material extracted by the solvent i. e. what is usually called the 

 „available" material, as differing essentially from that which is not so 

 extracted. 



„There is no fixed point when all the material soluble in the 

 medium employed will have gone into Solution, the extraction pro- 

 ceeds until an equilibrium is established between the material in the 

 solid State and that in Solution, and if the original material be homo- 



