No. 6] NEW MELOBESIEAE. 



2 times longer than broad, or 7—15 p !ong and 6—10 p broad, 

 frequently with much thinner walls than in the typical form and 

 often a rather distinct stratification. 



The conceptacles of sporangia are somewhat crowded in the 

 excrescences or branches, convex but very little prominent, not 

 sharply defined but frequently at length flattened in the central 

 parts, 350—400 p in diameter seen from above. The roof is in- 

 tersected with about 30 muciferous canals. The sporangia are 

 four-parted, 140 — 180 p long and 60—80 p broad, most frequently 

 with enduring interwalls. 



This form rather approaches in habit coarse specimens of 

 L. Sondert, a spedes also met with in the same place as the 

 present form, but differs as regards the conceptales as well as in 

 structure. 



The form genuina is known from Fuegia; f. valida from 

 San Diego, California (H. Hemphill — Herb. Fatiow, no. X); 

 f. crassiuscula from White^ Point, San Pedro, California, on peb- 

 les moving freely with the wave motion (Setehell, no. 1149), 

 and in tide pools San Pedro (Setehell, no. 1496 A). 



L. mesomorphum Fosl. mscr. 



Thallus leaf-like or lamellate, partly attached, horizontally ex- 

 tended, at length irregularly lobed and prolificating; profilications 

 semicircular or irregular, loosely spreading over each other, 300 — 

 500 p thick. Conceptacles of sporangia convex, subprominent, not 

 sharply defined, 350 — 600 p in diameter. 



This species closely approaches L. lichenoides f. heterophylla 

 in appearance, with frequently irregular and rather large prolifications 

 or lamels, the latter however more horizontal than generally to be 

 seen in the said form, partly with the edges bent a little upwards 

 partly downwards. The longest diameter of the specimens that I 

 have seen is 5 — 6 cm. 



On a section the central or lower cell-rows are rather regular, 

 the cells l 1 / 2 — 3 times longer than broad, or 12—20 p long and 

 5—8 p broad with rather thick walls, sending forth upwards a 

 vigorous perithallic layer the cells of which are square or more 



