ISSN:0368-2927    

DOI:10.1111/j.1095-8339.1929.tb00589.x

出版商:Blackwell Publishing Ltd    

年代:1929

数据来源: WILEY

摘要:

Summary.1The work is based on some 2300 experiments on seven species of the generaAspleniumandOsmunda, and gives the quantitative reaction to gravity of the fronds at stages previously defined as infant, adoleFcent, and mature (Waight, 1923).2Specific differences in the presentation time are distinct, in all buI one case, though slight coinpared with the generic differences, which are measured in hours forAspleniumand minutes forOsmunda.3O. cinnamonleais believed to be the most sensitive plant to the force of gravity as yet discovered, since its fronds, at inid‐adolescent stnges, will respond to a stimulus lasting ody 20 seconds.4The latent time shows relatively little specific difference, bnt is strikingly distinct generically.Osmundaresponds about three times as quickly asAsplerzium.5Presentation time and latent time for ferns may be represented by physiological graphs here termed grnviscripts; and certain generididions with regard to them are suggested.6The data at present available point to latent time as in general a far more constant quantity than presentation time. In a fern frond it is at its minimnm, and approximately constant throughout the adolescent stages.7It is pointed out that, since all characters possess taxonomic value in a truly Natural System, in cases of doubtful affinity, where easily available criteria have been found inconclusive, recourse may be tiad to physiological dat

ISSN:0368-2927    

DOI:10.1111/j.1095-8339.1929.tb00590.x

出版商:Blackwell Publishing Ltd    

年代:1929

数据来源: WILEY