Knowledge. 



VVith which is incorporated Hardwicke's Science Gossip, and the Illustrated Scientific News. 



A Monthly Record of Science. 



Conducted by Wilfred Mark Webb, F.L.S., and E. S. Grew, M.A. 



JUNP:, 1915. 



SOME NOTES ON THE BIOLOGY OF THE LARGER 



BRITISH FUNGI. 



By SOMERVILLE HASTINGS. M.S., F.R.C.S. 



{Continued from page 137.) 



There are also many other fungi which are the 

 causes of important and serious diseases of timber- 

 producing trees ; a few of them are here illustrated. 

 The Stumptuft [Armillaria mellea), which will 

 attack, not only conifers (pines), but also most 

 other forest trees, has already been mentioned 

 (see page 130). The Birch Polyporus [Polyponis 

 betulinus) (see Figure 134) kills young birch trees 

 within three or four years of the first infection by 

 its spores. The Beefsteak Fungus [Fistulina hepatica) 

 (see Figure 1 36) appears on an oak as a strawberry- 

 like knob, which develops into a thick, succulent, 

 shelf-like projection bearing the tubes from which 

 the spores are formed on its lower surface. The 

 mycelium usually takes several years to destroy 

 the oak tree on which it grows. The Prickly Cap 

 {Pholiota squarrosa) (see Figures 132 and 133) 

 grows on trees and stumps, and is probably a true 

 parasite. Polyporus schweinitzii (see Figures 1 37 and 

 1 38) is a large fleshy fungus which comes up in the 

 neighbourhood of pine trees. So rapid is its develop- 

 ment that grass, twigs, and even at times living 

 snails are surrounded and enclosed by it. It is 

 sometimes found quite close to the base of the tree 

 on which its mycelium grows, and when coming up 

 further away mycelial connections can always be 

 traced with some root of a tree. The fungus is 

 very destructive to pines and larches. 



There are eiIso fungi which grow parasitically on 

 members of their own class. Nyctalis is a toad- 

 stool which is found gromng on other toadstools. 

 The smaU incompletely expanded caps of Nyctalis 

 parasitica are seen in Figure 139 growing as a 

 parasite on a species of Russiila. \Vhen the little 

 caps open out the appearance is most curious. 

 There is a variety of truffle {Elaphomyces variegatiis) 

 (see Figure 140) which is fairly common in woods, 

 and forms its fructifications just beneath the 

 ground. These are very frequently infected by 

 a species of Cordyceps (see Figure 141) the fruits of 

 which appear above the surface of the soil as little 

 yello\vish-brown clubs. These last are found to be 

 invariably attached to the truffle, and the myceUum 

 from which they spring can be traced inside it. 



There are several other species of Cordyceps 

 which attack and destroy Uving insects. The 

 caterpillar fungus {Cordyceps militaris) (see Figure 

 1 35) is one of these. The fungus grows parasitically 

 on caterpillars, and its spores reach the insect's 

 body, either through the spiracles or by being 

 swallowed with its food ; but the insect is not 

 killed at once, for infection takes place very slowly, 

 and the chrysalis stage is usually reached before 

 the creature is finally destroyed. Its body is 

 then replaced by a dense web of fungus mycelium ; 

 but even in this state the outward form of chrysalis 



161 



