364 



SCIENCE 



[N. S. Vol. XLIII. No. 1106 



den at Hanover, New Hampshire, by fumes of a 

 tar compound known as tarvia which was melted 

 at a .time when atmospheric conditions were such 

 as to cause the fumes to hug the ground and blow 

 over the near-by garden, with the result that at 

 least twenty species were killed or severely in- 

 jured. The rapid and characteristic action of the 

 fumes seemed to favor certain conclusions. A 

 brief review of literature regarding smoke and 

 fumes is given, together vrith a brief description 

 of a series of experiments which indicate that the 

 following is true regarding the nature of the in- 

 jury. (1) The injury was due to the constituents 

 of the volatile substances which condensed in the 

 form of an oUy coating on the surfaces of the 

 plants. (2) The. in jury did not involve, to any 

 extent at least, the passage of gases through 

 stomata. (3) The injury was due to the action 

 of the fumes on aerial parts. (4) The injury 

 varied with the distance from the escaping fumes, 

 the temperature of the melting tar, and the age 

 of the plant structures. 

 A CanTcer of Apple Caused by Plenodomus fusao- 



maculans: G. H. Coons. 



A serious canker of apple has been found in 

 some orchards in northern Michigan. This canker 

 is characterized by the elongated lesions which 

 are commonly accompanied by cheeking of the 

 bark into small squares or rectangles. Lesions 

 are found extending along the limb, commonly on 

 the under side. These are the result of the kill- 

 ing of the bark in strips. In the older cankers 

 the killed bark drops off, leaving the bare wood. 

 One limb may show all stages of the trouble, from 

 freshly killed bark to the decorticated wood. In 

 the bark and especially on the bare wood pycnidia 

 are found in abundance. The wooly aphid by its 

 attack makes the canker very unsightly and 

 greatly interferes with the natural healing of the 

 wound. The causal relation of an associated or- 

 ganism, Aposphaeria fuscomaculans Saoc. has 

 been shown by the ordinary rules of proof. Ee- 

 cent work on the genera of the Sphaeropsidales 

 has given cause for rearrangement in the old gen- 

 era. From a study of the morphology of the or- 

 ganism associated with this canker, it has seemed 

 advisable to transfer the fungus to the genus 

 Plenodomiis. The physiological relations of the 

 causal organism has been studied at considerable 

 length, but an account of these is being published 

 separately in the Journal of Agricultural Be- 

 search. The results may be summarized by stating 

 that this organism shows relations to environmental 



factors, quite as sharp as those reported by Klebs 

 for Saprolegnia and other fungi. In particular 

 light was found essential for pycnidium formations. 

 Successful inoculations were obtained on the 

 limbs of Wealthy, Duchess, Jonathan and Ben 

 Davis apple as well as upon the Hyslop crab. 

 Other standard varieties seem more resistant, espe- 

 cially the Northern Spy. The fungus has been 

 successfully inoculated into pear, small cankers 

 being formed. No successful inoculations could 

 be obtained on apple leaves. Apple fruits of vari- 

 ous kinds are only very slightly invaded by the 

 fungus, no conspicuous rotting or spotting being 

 caused. The fungus shows marked attenuation 

 after being grown in culture. The disease has 

 been successfully controlled by methods commonly 

 advised for apple canker. 



Becent Contributions to our Knowledge of the 

 Genus Gymnosporangium : Feank D. Keen. 

 A little more than four years ago the writer 

 published an account of the genus Gymnospo- 

 rangium, ' ' A Biologic and Taxonomie Study of 

 the genus Gymnosporangium," which purported, 

 as the title indicated, to cover all of the informa- 

 tion available at that time relative to the biology 

 and taxonomy of these plants. Since that time 

 there have appeared more than a dozen papers 

 which have contributed additional facts to our 

 knowledge of this interesting genus. These con- 

 tributions have been of varied interest, some con- 

 cerning life-histories, others relating to anatomy, 

 physiology, taxonomy, distribution or pathologic 

 importance. The scattered condition of the addi- 

 tional information, as well as the accumulation in 

 the writer's hands of unpublished data, has sug- 

 gested the idea of bringing together in one ac- 

 count the more important facts. The appended 

 bibliography, in connection with the one formerly 

 given, will serve to direct any one to the original 

 sources provided exceptions may be taken to any 

 interpretations here given. With the exception 

 of a broad general statement it seems most satis- 

 factory to make an arrangement of notes under 

 specific headings since, for the most part, refer- 

 ences deal with individual species rather than the 

 genus as a whole. Among the more notable points 

 brought out in the various special papers may be 

 mentioned the report of another aecial host out- 

 side the Rosales, the finding of teliospores in the 

 species possessing uredinia, studies upon the effects 

 produced by the hosts upon the morphology of the 

 fungi, and active investigations of the species 

 causing diseases of economic importance. 



