190 ENDOSPOREAE [ORCADELLA. 



Genus 30. — ORCADELLA Wingate in Proc. Acad. Nat. Sci. 

 Phil., 1889, 280. Sporangia stalked ; sporangium-wall opaque 

 with granular deposits except in the upper part where it forms 

 a membranous lid. 



123. 0. operculata Wing. I.e. Plasmodium ? Total 

 height 0*4 to 0-9 mm. Sporangia scattered, urn-shaped or 

 subglobose, stalked, erect, 0-1 to 0*3 mm. diam., brown or 

 nearly black, provided with a convex or dome-shaped 

 dull yellow glossy lid ; sporangium-wall cartilaginous, 

 opaque from deposits of refuse matter ; lid membranous, 

 minutely papillose. Stalk cylindrical or subulate, furrowed, 

 nearly black, filled with dark refuse matter. Spores almost 

 colourless and smooth, 8 to 11 /x diam., yellowish or pink in 

 mass . — Mass. Mon., 49 ; Macbr. N. Am. Slime-Moulds, 158. 



PI. 149. — d. sporangia ; e. fragment of sporangium-wall and papillose lid, with 

 spores ; /. spore ; (United States). 



This minute species was first found by Mr. Harold Wingate in 

 Fairmount Park, Philadelphia, where it appeared in some abundance 

 on oak bark. In December, 1 908, a remarkable variety of O. operculata 

 was obtained in England by Mr. W. H. Burrell. The sporangia were 

 found on Hepaticae growing on beech bark, at Stratton Strawless, 

 Norfolk ; they differ from the type in having an ill-defined lid and in 

 the walls being dark and cartilaginous at the base only ; the remaining 

 sporangium-walls are membranous, pale olive-brown, translucent and 

 minutely papillose, and have a somewhat facetted appearance from 

 being marked with superficial patches of refuse matter ; the spore walls 

 are colourless, but the contents are pale rose-coloured ; this rosy tint 

 gives a striking appearance to the emerging swarm cells (see Burrell 

 in Trans. Norf. & Norw. Nat. Soc, ix. 106). Mr. Cran finds a similar 

 form near Aberdeen, associated with sporangia having well-defined 

 lids. 



Hab. On dead bark. — Norfolk (B.M. slide) ; near Aberdeen (B.M 

 3202) ; N. Germany (Herb. Dr. Bonn) ; Philadelphia (B.M. 1899). 



Order III. — Tubulin ace ae. 



Sporangia clustered, cylindrical or ellipsoid, stalked or sessile ; 

 sporangium-wall membranous, pale rufous, without plasmodic 

 granules ; spores minutely reticulated, 4 to 7 /a diam. 



KEY TO THE GENERA OF TUBULINACEAE. 



Sporangia cylindrical, compacted, with or without pseudo- 

 columella. (31) Tubieera. 



kltW' "• \ I"' f ;') Fig. 39. — Tubifera ferruginosa Gmel. 



-■Ji^i^gj Cluster of sporangia. Magnified 2* times. 



Fig. 39. 



