272 



THAXTER. 



MONOGRAPH OF THE LABOULBENIACEjE. 



Monoicomyces St. Helena Thaxter. Plate, XXXVI, figs. 8-9. 

 Proc. Am. Acad. Arts and Sci. , Vol. XXXV, p. 413. April, 1900. 



Pale yellowish or straw-eolored. Receptacle consisting of a triangular basal cell, and a squarish or 

 roundish subbasal cell which bears a small distal cell with a short terminal appendage separated from it 

 by a constricted blackish septum; two to four branches arise from the subbasal cell, normally fertile 

 and consisting of from two to five, usually three, superposed cells which are commonly somewhat inflated 

 distally, more so on one side, an upgrowth from which becomes separated so as to form a prominent small 

 cell which lies close against the base of the axis-cell next above and is simple or usually longitudinally 

 divided; in the former case bearing one, in the latter a pair of peculiar appendages distinguished by a 

 conspicuously blackened septum; the basal cell of this appendage usually blackened externally or often 

 wholly opaque the subbasal cell blackened externally about its characteristically geniculate base, its 

 terminal portion erect suffused with brown, or hyaline, and either terminating the appendage or followed 

 by two or three hyaline cells. Perithecium symmetrically inflated, slightly distinguished from the basal 

 cells, the tip small straight truncate tapering but slightly and abruptly distinguished. The antheridium 

 usually single on the fertile branch, replacing the characteristic sterile appendage at the base of the stalk- 

 cell of the perithecium, relatively small, its stalk-cells and those of the second tier about equal; the an- 

 theridium proper about as large as the basal part and hardly broader, its terminal cells developing, as in 

 the other species, long often flexuous hyaline upgrowths. Spores 38 X 3.5 /t. Perithecia 100-120 X 

 40-48 y. The stalk 34-50 X 25-27 y. Appendages of fertile branch 50-90 X 5 /i, Sterile part of re- 

 ceptacle 50-50 y. Greatest length to tip of perithecium 250-435 y. 



On abdomen and elytra of Oxytelus alutaccijrons Woll., British Museum, No. 411, Island of St. 

 Helena. On O. piceus Sim., Germany, and O. luteipennis Er., Algeria. Sharp Collection, Nos. 1170 

 and 1171. 



This species suggests Compsomyces in general habit, and the secondary fertile branches undoubtedly 

 spring directly from the subbasal cell of the receptacle. The sterile appendages of these branches are 

 very peculiar in appearance and are not unlike those of M. Leptochiri, a species which appears to be its 

 nearest ally. 



Monoicomyces Leptochiri Thaxter. Plate, XXXIV, figs. 39-40. 

 Proc. Am. Acad. Arts and Sci., Vol. XLI, p. 304. July, 1905. 

 Receptacle consisting of a main axis of superposed cells, usually long and slender, normally simple, 

 sometimes once to several times branched, the whole structure apparently a branch from the subbasal 

 cell of a small primary receptacle: the axis somewhat similar to that of Rhachomyces, consisting of a 

 series of superposed cells, variable in number (about twelve to twenty-five), each of which bears on one 

 side, so as to form a unilateral series, a pair of simple cylindrical few-celled appendages, which become 

 better developed from below upward; arising side by side, closely associated and appressed, characteris- 

 tically blackened at the base, which is usually indistinguishable from the small blackened cell from which 

 they arise, and which is obliquely separated just below each septum of the axis: this opaque region in the 

 lower cells of the axis, usually projecting characteristically like a notch or tooth: the cells of the axis 

 near its base deeply suffused or opaque; the suffusion becoming, from below upward, gradually associated 

 with the septum only: the axis in some specimens nearly hyaline throughout, with blackish-brown suf- 

 fusions at or about the septa. The paired appendages replaced somewhat irregularly below the perithe- 

 cium by antheridia of small size, resembling the appendages in general appearance when viewed laterally, 

 and usually terminated by two hyaline simple appendages of no great length. Perithecium solitary, 

 terminating the main axis, or its secondary axes; faintly yellowish, straight, slightly inflated, nearly 

 symmetrical, rather abruptly narrower at the tip, the apex rather small, symmetrical, truncate. Total 

 length to tip of perithecium 250-800 y, the axis about 18-20 y in diameter, Perithecium 70-90 X 18- 

 25 y. Longer appendages sometimes 50 y. 



