66 FUNGI INJURIOUS TO THE LARCH. 



the list of its hymenomycetous enemies. So recently as 1888* Von 

 Tubeuf discovered a disease on this Fir which may prove very 

 troublesome in wet districts. The tips of the branches droop, and 

 their leaves fall off, but remain hanging by means of a greyish 

 mycelium, which holds them together as if attached to the tips by 

 means of spiders' web. This mycelium gives rise to sporophores and 

 sclerotia, which prove it to be a Botrytis (B. Dow/lasii, n. sp.), and 

 if it turns out to be as destructive as some of its congeners (e.fj., 

 the Botrytis of the Lily-disease f) foresters will certainly have to reckon 

 very seriously with it. The damage is done by the mycelium penetra- 

 ting between the cells of the leaves and young shoots, and killing the 

 tissues forthwith. One source of danger is that this fungus can live 

 as a saprophyte in the dead foliage, etc., on the ground, as well as 

 parasitically in the living shoots ; and that it develops very efficient 

 resting organs known as sclerotia, which enable it to tide over 

 unfavourable seasons. 



It appears that this Botrytis has also been observed on the Larch, 

 and 011 Silver and Spruce Firs. It is as yet too soon to attempt to 

 decide as to the extent of the danger with which the fungus threatens 

 us ; we know very little, moreover, as yet, as to the capabilities 

 of the Douglas Fir itself in this country. Perhaps the greatest 

 damage so far done to it is by winds, but for my own part I feel 

 that this Conifer is still too new to the British Islands | to be finally 

 reported upon, and it is not surprising that we know as yet very 

 little about its diseases. It is with the Firs as with the Pines, as 

 regards the large number of diseases due to fungi : the American list 

 is very long, and our own is by no means either short or exhausted. 



The Hemlock Fir, Silver Fir and Spruce suffer in Germany from a 

 leaf-fungus ( ' Triehospliceria parasitica) which reminds one in many 

 respects of some of our Erysiphece. The seedlings of these and other 

 Firs are destroyed by Pliytophthora omnivora and by a Pestalozzia 

 lately re-examined by Yon Tubeuf. Almost as I write comes the 

 announcement of another disease of the Spruce, said to be found " all 

 over Germany," and due to the hitherto unsuspected parasitism of a 

 Septoria, and so the work goes on. 



III. The Larches. The European Larch is apt to suffer very much from 

 combinations of circumstances in the environment, when planted in this 

 country; and when one compares the conditions under which it is 

 attempted to grow it with those prevailing in the natural home of this 

 tree, the wonder is, surely, not that our Larches suffer, but rather that 

 any of them escape. The European Larch is a native of the Alps and 

 of the higher mountains of northern Europe, growing naturally at altitudes 

 which ensure a pure atmosphere, brilliant sunlight, plenty of distributed 

 moisture, and rapid drainage ; in its mountain home it has a relatively 

 long and thorough winter rest, from which, like Alpine plants generally, 

 it rapidly awakens late in spring, and then makes vigorous growth 

 through the brilliant and comparatively hot summer. 



In this country the diseases of the Larch are almost all initiated by late 

 frosts, damp soil, insufficient sunlight, and alternations of periods of drought 



* ' ' Beitrage zur -Kemitniss der Baum-Krankheiten " (Berlin, 1888). 



t Annals of Botany, Vol. II. 1888, "A Lily Disease." 



J I am told that it was only introduced in 1826. 



" Zeitschr. f. Pflanzenkrankh. " B. i. H. 3, 1891, p. 179, see also B. i. H. 1, 1891, p. 4? 



