No. 2] NEW SPECIES OR FORMS OF MELOBESIEAE. 9 



Melobesia (Heteroderma) coronata Rosan. 



Melob. p. 64. 



f. zonata Fosl. mscr. 



Thallus forming orbicular or suborbicular, concentric zonated 

 crusts on Lenormandia. Conceptacles subconical or conical, partly 

 150 — 200 j-t, partly 250—300 />- in diameter seen from above. 



According to a young authentic specimen of M. coronata in 

 my collection, the above plant appears to be so nearly related to 

 the said species that it scarcely may be considered more than a 

 form of it. The species is as yet but little known, especially with 

 regard to tendency of variation, and 1 do not yet exactly know 

 its structure. The form zonata differs in the surface being more 

 or less distinctly concentric zonate, and the crust somewhat thicker. 

 Besides, according to Rosanoffs description 1. c. the basal cells 

 seem to be a little shorter in the said form than in the typical one, 

 and often with thicker walls. On a cross section of f. zonata the 

 cells are frequently square or rounded, about 6 — 12 fi in diameter, 

 now however with the longest diameter in horizontal now in vertical 

 direction. The crust consists in the peripherical portions of a single 

 layer of cells with rather small cortical ones. It becoms thicker 

 towards the centre, where it is composed of at least up to four 

 layers of cells, perhaps even more in older crusts than that exa- 

 mined by me. 



There are to be found two kinds of conceptacles. A few ones 

 examined were empty. The one kind, the largest conceptacles, 

 are conical or nearly so, 250—300 p- in diameter seen from above 

 and probably identic with the cystocarpic ones described by Ro- 

 sanoff 1. c. The other and smaller conceptacles are subconical, 

 150 — 200 fi in diameter seen from above, being however uncertain 

 whether those of sporangia or perhaps antheridia. 



The form in question is attached to Lenormandia spectabilis, 

 here forming solitary crusts up to nearly 1 cm. in diameter, or 

 frequently smaller ones which partly anastomose. 



Occurrence. Hitherto only known from Port Elliot, South 

 Australia, collected by Miss Brumsert and kindly communicated 

 to me by Mr. Reinbold. 



