206 Professor Trail 012 the [sess. lii. 



below the leaf-blade. They are very common in Britain 

 and throughout Central Europe. 



Geum iirhanum, Linn. — Xear the Buarbra', in Hardanger, 

 at about 1500 feet above the sea, I found numerous leaves 

 bearing an abundant coating of Erineum gci, Fries, originally 

 regarded as a fungus. It is the work of mites {Pliytoptus), 

 and consists of patches of silky or woolly hairs, on either 

 surface of the leaf, but far more frequently on the lower. 

 Occasionally they are bounded by the veins, but more often 

 they thin out round their edges. The reverse surface of the 

 leaf, opposite each patch, is wrinkled and discoloured, becom- 

 ing yellowish or dull red. The hairs are usually white, but 

 show a tendency to become violet or rusty brown. Often 

 the leafstalks and stems also are affected. This gall is not 

 known as British, but has been recorded from Sweden (on 

 G. rivah), Thuringia, Austria, Switzerland, and France. 



Sedum Rhodiola, Linn. — Galls formed by a Phytoiitus were 

 common in Hardanger last August, in the Simodal, near Eide, 

 and on the way to Vossevangen, on the leaves and inflores- 

 cences of this Sedum. They are apt to form crowded masses, 

 which deform greatly the organs attacked ; all the young 

 leaves, or the flowers at the tip of a stem, may be so dis- 

 torted that the individual parts are scarcely distinguisliable. 

 AVhere they occur singly on the leaves they are usually 

 about 1 to 4 mm. in length, and rather less in breadth. 

 Each consists of a circular ridge of hypertrophied cellular 

 tissue, with an irregular warty or fissured edge, bent inwards 

 so as to leave only a narrow opening into the space within 

 the ridge. Into this space project small outgrowths from 

 the epiderm (jf the leaf, and l)etween these the mites may 

 be found. Tlie galls are yellowisli green, or violet passing 

 into purple. Specimens were sent to me in 1881, by Dr 

 I'nchanan White, from Ben lilabhein, in the island of Skye. 

 'J'lie gall was originally described l)y Dr F. Loew from speci- 

 mens collected in Lower Austria. 



Epihihium anrpidlfolmm, Linn. — Last August I found 

 upMii this plant, in the Siiiio(I;i] in Iliuilanger, the pseudo- 

 galls of one of the J'aijllukc. They consist of the leaf- 

 margin folded abruptly backwards, and flattened against 

 tlie lower surface, so as to leave only a, narrow space, in 

 wliich were larvcC of the insect. The tissue of the gall 



