132 G. ABBEY DESTETJCTION OF AN ElM-TREE. 



and continiies to enlarge and multiply its hyphoe or mycelium. 

 As shown at /, the contents of the original cell fonning the spore 

 are absorbed by the growing geiTQ-tube, now called a hypha [i), 

 and the cell (/) is emptied of the protoplasm transmitted from 

 the parent. The spore itself never enters the tissue of the tree, 

 but remains outside in the wound, as shown by the dotted line k. 

 It is the hyi)ha alone which enters the living tissues, and now 

 by its own efforts maintains its existence independent of the parent 

 cell. Though lost to view it grows and multiplies, forming 

 a mycelium or bundle of hyphse, and producing a white-rot in 

 the wood. In due course the fungus prejjares for reproduction, 

 the hyphfe thickening and pushing from their outward ends white 

 sporophores into the air, which thus appear above the surface as 

 incrustations or brackets, as shown in the figure I) at h. The 

 hymenium or fi'uit-producing surface is disposed on downward- 

 directed spines, as seen in the figure F at d, of unequal length, 

 and the basidia with their four slender processes termed sterigmata, 

 from each of which a spore is developed. These spores when ripe 

 are disseminated far and wide by the wind. 



Such is a brief outline of the life-history of the fungus Sydnum 

 dwersidens, a parasite on beech, birch, elm, hornbeam, and oak 

 trees. It always enters its host by a wound, never through the 

 unbroken cortex. 



"Whence came the spores which attacked this particular tree 

 is unknown, for there are no other trees in the neighbourhood 

 of St. Albans known to be infested by the same species. This 

 neighbourhood is, however, singularly rich in parasitic fungi, no 

 finer specimens of witches' -broom existing than on the hornbeams 

 near the lodge of Sopwell, and on birch at Cunninghame Hill 

 Farm. 



The dead tree in Victoria Street has had its limbs lopped, but 

 it ought to be bodily carted away for the sake of those which are 

 left, for both above and below where the once grand specimen has 

 been girdled, the bark is very light- coloured, evidence that its 

 organized substance is still being fed upon, and still fostering 

 fungi, some of the spores of which may be carried by the wind 

 to wounds on otlier elm -trees and do like damage. Its near 

 neighbour, the noble elm on the opposite side of Upper Lattimore 

 Road, ought also to be protected by a strong iron guard, else it 

 may share a similar fate. 



[March, 1897. — The tree has now been felled and removed. — Ed.] 



