Summary: Features include minute cups that erupt as spheres from pine and juniper needles, then open into reddish brown cups with irregular margins, the cup exterior darker reddish brown and pruinose, absent stem, and microscopic characters.
Microscopic: spores 12-14 x 3-4 microns, fusoid; asci 8-spored, reaching length of 80-100 microns and a width of 8-10 microns, narrowing downwards into an abrupt stem-like base; paraphyses filiform, enlarged in upper part, reaching a diameter of 2-3 microns, (Seaver), spores 10-16 x 4-6 microns, narrowly elliptic to cylindric, non-septate, guttulate; asci inamyloid; paraphyses colorless, (Hansen)
Notes: Cenangium acuum is found in NY and NJ to BC, and also Europe, (Seaver), and Denmark, Finland, Norway, and Sweden, (Hansen).
Habitat and Range
SIMILAR SPECIES
Cenangium ferruginosum grows only on Pinus. It has larger fruitbodies (0.2-0.3cm across) and the spores are broadly elliptic to fusoid (12-14 x 5-6 microns). (Hansen). R. Bandoni deposited collections at University of British Columbia of Cenangium alniellum, Cenangium griseum, and Cenangium vaccinii.
Habitat
on needles of Pinus strobus and other pine species, (Seaver), on needles of Pinus (pine) and Juniperus (juniper), early summer to early fall, (Hansen)