THE DISEASES OF CONIFERS. 



149 



I can recall no satisfactory case of fungus disease in this 

 Conifer. 



Little or nothing seems to be known of the diseases of 

 Cryptomeria, Taxodium, Cephalotaxus, Ginkgo (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 Hoffmann* attributes the 

 " Witches' brooms" of the Scotch Pine to these Pyrenomycetes. 

 Several iEcidia are known to grow on the scales of various 

 cones {e.g.,JEl. Strobilinum, conorum), and there is a curious 

 form in Finland and Sweden (^. coruscans) which so alters the 

 aspect of young Spruce-shoots that they resemble cones. t 



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 Mycor- 

 rhiza. 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 

 distichum, and the tubercles 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 CajJiiodium, and those of the Silver Fir, due to 

 Apiosporiim. Septoria Pini (Fuckl.) on the leaves of Picea 

 excelsa may be the spermogonia of the Hysterium nerviseqimm 

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

 certain y^czcZia on the Firs of the White Mountains only occur on 

 the dwarfed trees at great elevations, seems deserving of further 

 examination. 



A. CiLCurhitaria [C. pithy opliila, Fr.), reported as occurring on 



the cortex of living and dead branches of Conifers, also requires 



investigation. The same remark applies to Cooke's Asteriim 



cupresshm on leaves of Cupressus, and to Saccardo's Meliola 



Abietis on Abies, Ellis's Coryneum juniperinum on leaves of 



American Junipers, Cooke's Dothidea halepensis on Pines and 



D. sphcBToidea on Junipers, and the Pleospora laricina of Eehm ; 



* " Allgem. Forst- und Jagd-Zeitung," 1871, p. 236. 

 f 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,- 



