128 Transactions British Mycological Society. 



is separated from the stalk by a distinct constriction, in most 

 cases. This distinction between stalk and head, and the con- 

 tinuation of the glebiferous layer from arm to arm at its 

 base were noted by Fischer: the points are clearly shown in 

 Brittlebank's figure. 



The arms of L. australiensis are apparently glebiferous to 

 the apex: in section they are obtusely triangular, the rounded 

 apex of the triangle being on the inner side. The stalk in 

 cross section is composed of several layers (usually three) of 

 small chambers. 



In Lysurus Gardneri, the glebiferous layer is not continued 

 below from arm to arm. The stalk divides at the apex into 

 five small stalks, and these do not bear any glebiferous layer 

 for a length of two to four millimetres. Their structure in 

 this basal region is the usual chambered stalk structure, and 

 in cross section they show two large chambers. Above that 

 region, each arm becomes a simple tube, bearing on its outer 

 wall the closely-packed processes which constitute the glebiferous 

 layer. The diameter of the arm, which is about 3 mm. in the 

 stalk region, is increased to 6 mm. in the glebiferous zone, the 

 increase being due to the length of the processes. Towards the 

 apex, the glebiferous layer ceases, and the arm is continued as 

 a narrow simple tube. In this species, consequently, there is no 

 "head" sharply defined from the stalk: each arm is borne on 

 its own stalk. 



In section the arms of Lysurus Gardneri are oval, with a 

 narrow groove along the outer face. The groove results from 

 the absence of the glebiferous layer, with its long processes, 

 from a narrow longitudinal band. The stalk is composed, as 

 a rule, of a single layer of chambers, greatly extended longi- 

 tudinally, but it may have two layers. 



The discussion as to the identity of Lysurus Gardneri and 

 Lysurus australiensis has usually centred on the minor point 

 whether the arms are united or not at the apex. In Lysurus 

 Gardneri, each arm is continued as a narrow tube to the apex, 

 where it is united with the other arms, the tube structure 

 being continuous over the apex. This feature is constant in 

 all the fresh specimens examined, and it is clear from the 

 structure that any separation of the arms could only be the 

 result of an accidental fracture. In Lysurus australiensis, the 

 arms are said to be usually free at the apex, but specim.ens are 

 found in which the arms are united. In one of the specimens 

 sent me by Mr. Cheel, one of the arms is subacute and closed 

 at the apex ; the remaining four are perforate and truncate at 

 the apex, and one of them bears at the top a short length which, 

 from its expansion upwards, evidently belongs to one of the 



