The little orange "gumdrops" in this image (about 150 µm
across) are formed right on the surface of standing-decaying leaf blades
of smooth cordgrass. They are ascomata of Hydropisphaera
erubescens, an hypocrealean ascomycete. Here are the ascospores of this species (about 21
µm long, in the ascus on left and free on right). This species
occurs
at highest frequency (to 78% of blades) in summer, and has not been found
north of Georgia. Amy Rossman has found that rDNA base-sequencing
indicates that this species is identical to Hydropisphaera
erubescens from terrestrial leaf litter. H.
erubescens from smooth cordgrass occurs at heights on
shoots where it is regularly immersed in seawater, so it is
at least a facultatively marine fungus. Other hypocrealean species
are mycoparasites used in biocontrol; could the
cordgrass Hydropisphaera be parasitic on other cordgrass
ascomycetes growing within the standing-decaying blades? See Newell,
SY. 2001. Spore-expulsion rates and extents of blade occupation by
ascomycetes of the smooth-cordgrass standing-decay system. Bot. Mar.
44:277-285.