54 ENDOSPOREyE. [PHYSARUM. 



12 to 15 p., and are strongly spinulose ; while in others they are 

 smoother, and average 9 to 11 /A diam. The lime-granules in the 

 sporangium-wall frequently coalesce into vitreous superficial scales or 

 coarse particles, and those in the lime-knots become transparent and 

 lose their granular character. This feature is occasionally, though 

 rarely, met with in other species. In preparations in water of highly 

 calcareous sporangia part of the lime is found to dissolve, and on 

 drying to crystallise on the slide in particles resembling those described. 

 A cultivation from an extensive growth of plasmodium exhibited 

 the forms o, /3, and y in the development of the sporangia. 



a. Sporangia ovoid or reniform, laterally compressed, on short 



black or grey stalks, or sessile. 



(3. Sporangia ovoid or reniform, on white stalks O5 mm. long, 

 y. Plasmodiocarps lobecl and confluent. 

 8. Sporangia subglobose, stipitate. 



Plate XVI., A. a. sporangia of vars. a, /3, and 7, developed from the same 

 plasmodium, x 20 ; 1. capillitium and spores, x 280 ; c. spore, x 600 

 (England). 



B. a. sporangia of vars. a and 7, drawn from the type specimen of Pliy- 

 sarum PMllipsii, x 20 ; &. capillitium and spores, x 280 (England) ; c. 

 sporangia of var. 5, x 20 ; d. capillitium and spores, x 280 ; e. spores, 

 x GOO (Iowa, B.M. 807). 



Plate XVII., A. a. sporangia from type of P.nicaraguense Macb., x 20 ; 

 I. capillitium and spores, x 280; c. spore, x 600 (Nicaragua). 



The specimens named P. ncphroideum Host. (Strassb. Herb.) are the 

 form a. The type of P. ccmdidum Host., from Juan Fernandez 

 (K. 510), is the form /3 ; in some of the sporangia the lime-knots coalesce 

 to form a central mass ; that of P. Phillips-it Balf., from Phillips' 

 Herb., shows the forms a and y ; and that of P. limdum var. conglobaiam 

 Host., from Ceylon, No. 55 (K. 1244), is the form a with short black 

 stalks ; that of P. affine Kost., from Cuba, No. 907 (K. 1350), is the 

 form /3 with white stalks. Didymium botry aides Berk, in Herb., from 

 New Zealand (K. 1523) a type of D. radiatum Mass. is the form a. 

 D. 2~>rumosum Berk. & Curt., from Cuba (K. 1515), given by Rostafinski 

 as a synonym for P. nephroideum (Rost., App., p. 5), is the form a. P. 

 ylaucuui Phill., in Phillips' Herb., is form a both with short black stalks 

 and sessile. In Berkeley's Herb, there are two gatherings from Ceylon 

 of one species under the name of P. nutans : one of these (K. 1406) 

 is the type of Tilmadoche reniformis Mass., the other (K. 1407) the type 

 of Didymium echinospora Mass. It is a form with compressed reniform 

 sporangia on long buff stalks ; capillitium with large fusiform or 

 branching lime-knots and short connecting hyaline threads ; spores 

 dark purple-brown, spinose, 13 to 15 p. It appears to be a variety 

 of P. compressum, form a, differing from the type in the long slender 

 stalk. 



American specimens, with nearly globose sporangia, and buff or 

 white, long or short, stout stalks, from Professors Farlow and Macbride, 

 appear from the capillitium and spores to be P. con^ressum, but a well- 

 marked variety. They are more symmetrical than European forms, 

 and are distinguished as var. 8. 



The specimen from Nicaragua named P. nicaraguense Macbride 

 (figured on Plate XVII., A.) corresponds with a long-stalked and 

 lobed form of P. compression from Ceylon (B. M. 420), part of which 

 gathering is shortly stalked or sessile ; it also approaches a specimen 

 from Luton (L:B.M.30), in which the lobed and confluent sporangia 



