138 THE BRITISH XRUFrLES. 
Tuber is said to be strongly alliaceous. — Tuber macrosportm, Vitt. Mon. 
Tub. t. i. f. 5 ; Tul. Ywng. Hyp. t. 17. f. 8 ; Berk, and Br. Ann. Nat, 
Hist. No. 5S0; Berk. Outl. p. 376. 
3. Tuber bitumiuatum, B, and Br. Tuber black, globose or ovate and 
regular. Warts small and polyhedral^ with a deep hole excavated at the 
base of the tuber. Veins loosely coherentj for the most part originating 
frona the margin of the basal hollow. Asci oval, with long pedicels. 
Sporidia tawny, ovate, loosely cellulose. Odour strong of pitch and 
Horseradish, " Closely allied to T. astivum, Vitt., but easily distin- 
tinguished by the odour; it differs also in the general form, being 
much more regular and the warts smaller^ and in the existence of a 
basal cavity prolonged into the substance of the fungus, which is thus 
very light conipared with T. cestivum. Tlie veins cohere very loosely, 
so that it is difficult to cut the plant in half without breaking it into 
frustules. It shrinks very much in drying. The sporangia have much 
longer stalks than in T, astivum. The sporidia closely resemble those 
of that species, but are slightly longer compared with their width, and 
bave somewhat shallower cells. It ranges from the size of a walnut 
to that of a hen's egg." (Berk, and Br. Ann. Nat. Hist. No. 581.) 
4. Tider scleroneuron, B. and Br. Tuber red-brown, cartilaginous, 
globose, lobate; minutely warted, nearly smooth, rimose. Veins irre- 
gular, broken, springing from the cracks in the peridium. Cinereous 
towards the centre, red-brown at the circumference. Sporidia red- 
brown, ovate, minutely cellulose. Odour faintly aromatic. '^This 
species differs from T. rufim, Vitt., in its firmer cartilaginous texture, 
deep red-brown colour, in the form of its sporidia, which are ovate, not 
elliptic-elongate, and in its faint aromatic odour. The veuation also 
is more broken and interrupted. Tuher rufum, Vitt., appears to be its 
nearest ally. When dried, T, sderonevron becomes as hard as a piece 
of wood." (Berk, and Br. Ann. Nat. Hist. No. 582.)— Bowood, "Wilts, 
October, 1857. 
5. Tuber excavatur/i (Tab. XXX. Fig. 1-6), Vitt. Subglobose, about 
an inch in diameter. Peridtum discrete, ochraceous, minutely vemicose 
firm. Flesh horny, cinereous-red, liver-coloured or tawny. Veins 
pallid-ochraceous. The substance falls away in the centre so as to 
leave a cavitj^, which has an opening at the base of the tuber. Asci 
numerous, ellipsoid, 1-4-spored. Sporidia ellipsoid, yellowish or pallid- 
tawny; epispore largely faveolo-plicate.— r^/5^r excavatuni,N\li^6:\m, 
