70 FUNGI INJURIOUS TO VARIOUS CONIFERS. 



and infects the leaves but does not get beyond the production of 

 yellow humps. 



Whether further researches show that these results are confirmed or 

 not, it is now certain that we have in these forms of Gymnosporanyium 

 and Rwstelia parasitic fungi which are highly polymorphic,* and a 

 number of specialised races or varieties are heteroecious between 

 Cupressinese and Rosacese (as many other " Rust-fungi " are between 

 GraminesB and dicotyledonous plants), causing diseases of the cortex 

 and wood of the one, and of the leaves in the other. Obviously 

 it is advisable to take these facts into account where it is wished to 

 grow either of these classes of plants in the best way. 



Y. Other Conifers. Conclusion. Ayaricus melleus is recorded by Farlow 

 as occurring on Chamfficyparis sphceroidea (Cupressus thyoides) and the same 

 authority mentions Botrytis vulgaris on Sequoia ; whether these are 

 parasitic, I do not know, and in fact the whole of the very long list 

 of American Conifer-fungi wants careful overhauling before we can 

 decide as to their share in producing diseases. I have found the roots 

 of Wellingtonia badly infested with mycelium which seems to be that of 

 a Hymenomycete ; and Araucarias occasionally suffer from similar 

 forms. 



The Yew seems to be very little affected with fungi ; at least I can 

 recall no satisfactory case of fungus disease in this Taxad. 



Little or nothing seems to be known of the diseases of Cryptomeria, 

 Taxodium, Cephalotaxus, Gingko (Salisburia), or Podocarpus and other 

 allies ; and I know of no records of specific diseases of the Cedars. 

 Two species of Cladosporium are said to injure Pines, and Hoffmannt 

 attributes the " Witches' brooms " of the Scots Pine to these Pyre- 

 nomycetes. Several /Ecidia are known to grow on the scales of various 

 cones (e.</., ^E. Strobilinum, ^E. conorum), and there is a curious form 

 in Finland and Sweden ( jE. coruscans) which so alters the aspect of 

 young Spruce-shoots that they resemble cones. J 



Several Conifers, especially the Pines, are known to have subterranean 

 fungi at their roots, but apart from any symptoms of disease. The 

 fungus causes the attacked root to swell and alter its form, and the 

 symbiotic compound body is called a Mycorrhiza. These curious 

 phenomena lie outside of my present theme, however, as also do the 

 no less remarkable abnormal-looking outgrowths so-called " knees "- 

 from the roots of Taxodium distichwu, and the nodules caused by 

 fungi on the roots of Podocarpus. 



More to the point at present are the cases of " sooty-leaves " of 

 Araucaria excelsa and the Yews, due to the black mycelium of species 

 of Capnodiwn, and those of the Silver Fir, due to Apiosporium. 

 It has been suggested that Septoria Pinii occurring on the leaves of 

 Picea excelsa may be the spermogonia of the Hysferiwn (Lopliodermium) 

 nervisequum found on that plant. An observation of Farlow's in 1884, 

 that certain ^Ecidia on the Firs of the White Mountains only occur 

 on the dwarfed trees at great elevations, seems deserving of further 

 examination. 



* I purposely omit discussion here of such points as Kienitz-Gerloff s discovery of alleged 

 Urt do-spores among the Teleuto-spores of these fungi. 



t "Allgemeine Forstliche und Jagd-Zeitung, " 1871, p. 236. 



J Not to be confounded with the cone-like deformations on the same plant due to insects 

 (Chermes viridis}. 



" Appalachia, " Vol. III. part 3, Jan. 1884, quoted by Sorauer, p. 249. 



