850 EXPERIMENT STATION RECORD. 



The hollyhock rust, its nature and developmental phases, J. Ebiksson 

 (Compt. Rend. Acad. Sci. [Paris], 152 {1911), Wo. 25, pp. / 776-/ 779). —The 

 author gives the results of a 2-year biological study of this rust {Puccinia mal- 

 vaccarum). Two corumou hosts were found, viz, AJthwa roaca and Malta 

 silvestris, but many otlier species of tbe IMalvacese are also attaclied by the rust. 



It is claimed that tlie dissemination of this rust from one locality to another 

 is through diseased seeds or diseased rootstoclcs. At first, that is during the 

 first 3 months, all the stallis remain unaffected, and they will continue so if 

 the seeds from which they came were healthy, but if the seeds were from 

 diseased plants the rust will suddenly appear vigorous and fully developed on 

 the leaves. This first appearance is called the primary eruption, and differs 

 from the latter and more irregular pustules wLich successively appear on all 

 parts of the plant, called the secondary eruption of the rust. The primary 

 outbreak originates from the interior of the host, while the secondary infection 

 is produced from the sporidia of the primary sori. 



The rust winters over in the rootstocks of A. rosea in the form of mycoplasm 

 which enters into a kind of symbiosis with the living cells of the host, and in 

 the early spring gives rise to the primary infection. In the autumn the sori 

 produce 2 forms of spores similar morphologically, but germinating differently. 

 The greater part of these spores on germination form short, thick promycelia 

 which produce sporidia. The, other type of spores on germination form long 

 filaments or hyphte, slender and straight, terminating in very short joints 

 which fall off as conidia. The usual type of sporidia on germination forms a 

 vesicular filament which penetrates into the palisade cells and in 10 to 20 

 days produces new sori. 



The conidia on germination empty their contents as a plasmic mass on the 

 epidermis of the leaf, and penetrating into the cells of the epidermis pass from 

 there into the neighboring cellular tissues, where they take on a mycoplastic 

 life. After this no evidence of rust infection is seen, but the infected leaves 

 grow vigorously and seem perfectly healthy. In the embryo of the seed ob- 

 tained from diseased plants there is no trace of mycelium, and yet it is from 

 these seed that the diseased plants are developed. 



On the wintering- over of certain Erisiphaceae, V. Peglion (Atti R. Accad. 

 Lincei, Rend. CI. Sci. Fis., Mat. e Nat., 5. ser., 20 {1911), I, No. 9, pp. 687-690).— 

 The author reports the wintering over of O'idium quercinum in the conidial 

 stage in the buds of the oak, O. farinosum in apple buds, and 0. leucoconium in 

 the winter buds of roses. 



On the artificial production of the black canker of the chestnut, G. Briosi 

 and R. Faeneti {Atti R. Accad. Lincei, Rend. CI. Sci. Fis., Mat. e Nat., 5. ser., 

 20 {1911) I, No. 9, pp. 6^8-633).— The authors claim to have produced all the 

 symptoms of black canker by inoculating the living bark of the chestnut with 

 the spores of Coryneum pemiciosum, and also with the ascospores of its perfect 

 stage {Melanconis pemiciosa). 



ECONOMIC ZOOLOGY— ENTOMOLOGY. 



Revision of the spiny pocket mice (genera Heteromys and Liomys), E. A. 

 Goldman {U. 8. Dept. Agr.. Bur. Biol. Survey, North American Fauna No. S4, 

 pp. 69, pis. 3, figs. 6). — The spiny pocket mice, although of small size, are of 

 considerable economic importance owing to the fact that they feed chiefly on 

 seeds, including weed seeds, corn, wheat, and beans. They are widely distrib- 

 uted in the drier parts of North America. " While apparently not so injurious 

 to ci'ops as some other rodents, these mice, in some places, are among the most 



