physarum] physaraceae 61 



with a hypothallus of branching fulvous strands ; sporangium- 

 wall of two closely connected layers enclosing abundant 

 deposits of lime-granules. Stalk 0-1 to 0-5 mm. long, 

 fulvous, weak and almost membranous, expanding below 

 into strands of the hypothallus. Columella none. Capillitium 

 a dense persistent network of nearly colourless threads, 

 with membranous expansions at the axils, and with scattered 

 angular often branched pale yellow lime-knots. Spores 

 dark purple-brown, spinulose, 10 to 12 /x diam. Leocarpus 

 fulvus Macbr. N. Am. Slime-Moulds, 82 (1899). 



PI. 66. — a. sporangia ; b. capillitium and spores, with fragment of sporangium- 

 wall ; c. spore ; (Colorado). 



The type of this species was gathered by Mr. E. Bethel " on living 

 willow," growing in snow, 11,000 feet altitude, Loveland Pass, Colorado, 

 in June, 189G. Dr. Sturgis has kindly allowed us to examine two 

 other specimens, both of which were sent him by Mr. Wingate under the 

 name " Physarum albescens Phillips," and which he agrees with us in 

 thinking should be placed under P. fulvum. He has not been able to 

 trace the origin of the name " P. albescens " Phillips, and apparently 

 it has never been published. One specimen is marked " Iowa, leg. 

 Holway, ex herb. Rex," the other " Louisiana, leg. Langlois, ex herb. 

 Ellis." In both gatherings the pale cream-coloured sporangia are 

 either subglobose and sessile, or form short plasmodiocarps, and show 

 but little development of hypothallus ; they agree in other respects with 

 the type of P. fulvum, except that the lime-knots in the Louisiana 

 specimens are smaller and brighter yellow, and the Iowa specimen 

 has rather paler and smoother spores that measure only 8 to 10 /a. 



Hob. On leaves and twigs. — Near Denver, Colorado (B.M. 2147) 



26. P. penetrale Rex in Proc. Acad. Nat. Sci. Phil., 1891, 

 389. Plasmodium ? Sporangia stalked, erect, ellipsoid, or 

 globose, 0-3 x 0-5 mm. diam., grey or pale greenish-yellow, 

 smooth ; sporangium- wall membranous, rather firm, semi- 

 transparent, with innate scattered clusters of pale yellow or 

 white lime-granules, rupturing when mature into from two to 

 four segments. Stalk erect or curved, 0-5 to 2 mm. high, 

 slender, subulate, smooth and solid, translucent, dull red or 

 golden-red. Columella formed by a continuation of the stalk, 

 penetrating the sporangium to about four-fifths its height, 

 slender, scarcely tapering to the abruptly conical or expanded 

 end, yellow. Capillitium a close network of hyaline threads 

 with triangular expansions at the axils of the branches, 

 arising from the whole length of the columella, persistent after 

 the dispersion of the spores ; lime-knots scattered, small, 

 rounded, yellow. Spores pale brownish-violet, delicately 

 spinulose, 5 to 6-5 jx diam. — Macbr. N. Am. Slime-Moulds, 55. 



PI. 36. — a. sporangia (Ireland) ; 6. sporangium after dispersion of spores showing 

 the long columella, from a glycerine preparation ; c. capillitium and spores ; d. spores. 



An immature specimen of this remarkable species occurs in the 

 Strassburg collection named by Rostafinski " Craterium leucocephalum, 



