72 J. SAUNDERS — witches' BROOMS. 



Luton. In this instance, as in the common ehn at Limbury, the 

 l)room rises erect from the branch from which it originates. The 

 compact, ascendiniJ^ habit of the launches of the l^room is very 

 unlike the diverging branching that is so characteristic of the 

 wych ehn. The elevated position of the broom renders a close 

 inspection impracticable. In the early months of the years 

 1904 and 1905 there were no flower-buds on the broom, 

 although the highest branches of the tree were covered with 

 them. On 24th April, 1904, the leafing of this tree and its 

 associated broom appeared to be simultaneous. On 24th August, 

 1904, the foliage of the broom was all withered except on two 

 or three very young t^^^gs. By 17th Septeml)er all its leaves 

 had fallen, while those of the healtliy portions of the tree 

 remained in position for a fortnight later. 



Birch (Betida alba, L., and B. verrucosa, Ehrh.). — The silver 

 birch, including at least the two forms B. verrucosa and 

 B. glutinosa, is peculiarly susceptible to the disease under 

 consideration, and the curious gro-fti:hs on these trees usually 

 arrest attention from their striking resemblance to badly- 

 constructed bii'ds'-nests. 



The exciting cause is the presence of a parasitic fungus, 

 Exoascus Betulinus, Eostr. (=E. turgidns, Sadeb.). In 'Country 

 Life,' 28th May, 1904, p. 792, it is stated that " The mycelimn is 

 very minute and works just below the bark, stopping the proper 

 development of the part it attacks, and causing this mass of 

 sickly shoots." 



The fruiting-stage appears on the under-side of the leaves in 

 May and June, and can easily be seen with a pocket-lens ; 

 a much higher power being necessary to distinguish the structui'e 

 of the asci and contained spores. The disease is always accom- 

 panied by a crumpling of the leaf. 



The affected twigs are short- - lived, usually not attaining 

 a greater age than two or three years, sometimes only one. 

 Other small branches are developed in succession, so that each 

 broom contains a large proportion of dead material as well as 

 living. Hence the opaque appearance of the older growths. 



This iiisease is quite distinct from another to which these 

 trees are subject. In this the leaves are infested by minute 

 mites, Eriopliyes rudis, Canestrini, the irritation set up by them 

 causing a number of diminutive brooms to appear as outgrowths 

 from the diseased buds. (See ' Country Life,' 28th May"^ 1904.) 

 This is confirmed by Mr. E. Connold, the author of a work on 

 British Galls, in a letter to the writer dated 29th April, 1902. 



A fine example of Witches' Brooms on birch is present in the 

 grounds of Mr. GT. Plummer, The Villas, Lviton. The tree has 

 borne these growths for at least 25 years, and the l«x)onis become 

 more numerous with advancing age, so that at the time of writing 

 (1906) there are on it at least thirty masses, varying in size from 

 a few inches to several feet in diameter. Although so laden with 

 these parasitic growths, the general health of the tree does not 



