ISSN:0027-5514    

DOI:10.1080/00275514.1942.12020866

出版商:Taylor&Francis    

年代:1942

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1942.12020867

出版商:Taylor&Francis    

年代:1942

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1942.12020868

出版商:Taylor&Francis    

年代:1942

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1942.12020869

出版商:Taylor&Francis    

年代:1942

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1942.12020870

出版商:Taylor&Francis    

年代:1942

数据来源: Taylor

摘要:

SUMMARYThe genusBrevilegniawas established by Coker on the basis of the following characters: (1) the presence of a depauperate dense mycelium; (2) the development of zoösporangia which discharged the spores by the irregular rupture of a sporangium wall that disappeared after maturity; (3) the variability in sporangiospore size and the frequent suppression of motility; and (4) the formation of small, monosporic oögonia. The species and varieties were separated from one another because of such properties as the size and shape of the zoösporangia, the presence or absence of antheridia, the motility or lack of motility of the zoospores, and the formation or absence of gemmae.These specific and varietal characters, however, were greatly influenced by the environmental conditions. The width and general shape of the sporangia changed not only with the differences in the quality and quantity of the surrounding water, but also varied somewhat within a constant environment. Zoospore activity is too little understood to be used as a character for the delimitation of a species or variety. Gemma formation is partially dependent on the condition of the enveloping medium, whereas the appearance of antheridia is controlled by the degree of aerobiosis of the surrounding water.In addition, the sporangia dehisced exactly as inThraustothecawith fragments of the outer wall persisting throughout. Hence,Brevilegniawas placed as a subgenus underThraustotheca, and all the species exceptT. bisporaincluded underT. unisperma.

ISSN:0027-5514    

DOI:10.1080/00275514.1942.12020871

出版商:Taylor&Francis    

年代:1942

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1942.12020872

出版商:Taylor&Francis    

年代:1942

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1942.12020873

出版商:Taylor&Francis    

年代:1942

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1942.12020874

出版商:Taylor&Francis    

年代:1942

数据来源: Taylor

摘要:

SUMMARYA root rot ofChamaecyparisoccurring in Oregon and Washington is attributed toPhytophthora lateralis.The fungus invades the young roots and eventually girdles the trunk; characteristic color changes of the foliage accompany the destruction of root and stem tissues and infected trees are killed.In culture the causal fungus grows slowly on agar media. The optimum temperature is about 20°C.; growth is reduced at 25°C., and inhibited at 30°C.The disease has been identified inChamaecyparis Lawsonianavar.alumi, C. Lawsonianavar.erectaandC. obtusavar.gracilis.

ISSN:0027-5514    

DOI:10.1080/00275514.1942.12020875

出版商:Taylor&Francis    

年代:1942

数据来源: Taylor