280 Floristik, Geographie, Systematik etc. 



Rayner, M. C, The Ecology of Calluna vulgaris. (New Phvto- 

 logist. XII. 2. p. 59-77. 1 pl. 2 figs. 1913.) 



In continuation of an earlier communication (Bot. Cent. 120 

 p. 156) of the occurrence of Calluna on soils with low calcium car- 

 bonate content and its absence on other soils, an interesting series 

 of culture experiments is here described. Pot cultures in "■Calluna 

 soil" and in "chalk soil" provided material for the study of germi- 

 nation and growth; the latter is normal in the Calluna soil and 

 abnormal in the chalk soil. Abnormality is indicated by reduced 

 germination capacity, retarded germination, arrest of root and cur- 

 vatures of the growing region, arrest of shoot, and by small size 

 and red colouration of leaves. Normal roots are infected on germi- 

 nation by an endotrophic mycorhiza, whereas abnormal ones have 

 colonies of bacteria especially around the root-tip, and there is also 

 a diminution of vigour in the growth of the mycorhizal fungus. 

 Abnormal conditions can be induced in seedlings grown in Calluna 

 soil by watering with extracts of the unfavourable soil. When unste- 

 rilised seeds are grown in agar media, the development of the 

 microflora is such that with Calluna soil extract the mycelial con- 

 stituent is predominant, while with extract of chalk soil the bacteria 

 prevail. The mycorhizal fungus arises from the seedcoat which is 

 infected while still in the ovary; the embryo and endosperm are 

 free. Seeds can be sterilised and germinated in a sterile condition 

 by means of special culture tubes described and illustrated; the 

 seedlings are normal but in absence of infection there is complete 

 arrest of root formation. This indicates that the relation between 

 Calluna and fungus is obligate. The soil preference of Calluna depends 

 on the maintenance of a balance between the roots and the con- 

 stituents of the micro-flora. The bacterial colonies are regarded 

 either as pathogenic or as indications of soil conditions unfavourable 

 to the fungus. W. G. Smith. 



Smith. W. G., Raunkiaer's "Life-forms" and Statistical 

 methods. (Jour. of Ecology. I. 1. p. 16—26. 1913.) 



An abstract dealing with 7 papers of Raunkiaer, intended to 

 introduce his methods and views to English readers. The "Life- 

 forms" include phanerophytes, chamaephytes and other types foun- 

 ded by Raunkiaer; these are defined and examples are given in 

 tables. The methods described in "Formations undersögelse og 

 Formationsstatistik" are dealt with in some detail, with some criticisms. 



W. G. Smith. 



Stockberger, W. W., The Geographie Distribution of 

 Tannin Plauts. (Journ. Amer. Leather Chem. Assoc. Jan. 1913.) 



The subject matter of this paper is treated under the heads of 

 Gymnospermae, Monocotyledones, Dicotyledones. The principal 

 plants considered are Aveca catechu, species of Persea, Nectandra^ 

 Avicennia, Rhisophora, etc. Harshberger. 



Sudworth, G. B., Forest Atlas. Geographie Distribution 

 of North American Trees. Part. I. Pines. (Forest Service. 

 U. S. Dept. Agric. 1913.) 

 This large folio, issuedas a publication of the U. S. Forest Service, 



is the first part of an atlas which will represent the geographic 



