TWO NEW VARIETIES OF LAMPKODEliMA. 



Br G. Lister, F.L.S. 



(Plate 552.) 



Two interesting forms of Lamprodenna, differing in some respects 

 from an J hitherto described, were obtained last spring by Mr. H. J. 

 Howard in the Whitlingham Woods, near Norwich. They occurred 

 close together in two beds of beech-leaves, several yards apart, and 

 some distance below the surface, and also on the leaves of two small 

 box-plants, around which the beech-leaves were thickly heaped. Thev 

 were first noted on April 3rd, when specimens were collected in 

 good condition. On May 11th, when the woods were revisited, care- 

 ful search resulted in sporangia being found on from thirty to forty 

 leaves; many were in a weathered condition, others were still in good pre- 

 servation. On the whole, it seems probable that no further develop- 

 ment of sporangia had taken place between the two dates of collecting. 



The two forms may be referred to, for convenience, as forms A 

 and B. Form A appears to be a sessile variety of Lamproderma viola- 

 ceum (Fries) Rost. ; form B bears considerable resemblance to L. atro- 

 sporuin Meylan, a species fairly common in the Jura Mountains and on 

 the Swiss Alps, but not recorded from any other locality hitherto. 



Form A (fig. 1) was by far the more abundant, and may be 

 described first. The dark brown iridescent sporangia are either crowded 

 together or scattered over the surface of the beech-leaves, a few only 

 are on box-leaves ; they are sessile, subglobose, or hemispherical on a 

 broad base, and measure 0'5 to 0*8 mm. ; a few form long plasmodio- 

 carps constricted at intervals. The sporangium-walls are mottled 

 with purplish shades, and, though somewhat persistent, at length 

 break away in large fragments. The columella, in many sporangia, 

 is represented only by a slight central thickening of the membranous 

 floor; in other sporangia it is better develojDed and forms a short 

 black column which may reach to about a third the height of the 

 sporangium : very rarely it is a more massive structure and expands 

 below to form the rudiment of a stalk. The pale purplish capillitium- 

 threads are combined into a dense network with membranous expan- 

 sions at the axils of all the branches ; a few of these expansions 

 form conspicuous dark strands, such as are not infrequently seen 

 in irregular developments. The spores are pale purplish-brown, 

 closely and minutely spinulose, 10 to 11 /x, diam. 



Although differing in many resjDects from the typical i. violaceum 

 with its slender black stalks, and capillitium forming a tuft of threads 

 repeatedly branching at acute angles, form A is probably a weak 

 sessile growth of this species. We propose to name it L. violaceum 

 var. dehile Gr. Lister & Howard. 



More or less sessile forms have been met with occasionally before, 

 but in almost all the sporangia the columella and capillitium have 

 been normally developed. 



Interesting light is thrown on the variation which may occur 



in one growth of L. violaceum by the study of a specimen found 



on the Weissenstein, in the Jura Mts., 4000 feet alt., in June 1910. 



As in the Norfolk gatherings, the sporangia were on beech -leaves, but 



JouENAL or Botany. — Vol. 57. [Feeeuaey, 1919.] d 



