The purplish-black rods projecting out of this seedhead of
smooth cordgrass (Spartina alterniflora) are the "ergots"
(sclerotia) of Claviceps purpurea, an ascomycete that is an
obligate parasite (lifecycle diagram)
(field view). The fungus replaces the
tissue of the ovule, and draws all of its nutrients from the
plant's attempting to feed the ovule. The moldiness at the base of
some of the ergots in this image probably represents a fungal
hyperparasite (Fusarium sp.). The ergot eventually falls to
the sediment and overwinters. Ascomatal stromata grow out from the
ergot in the following year, and these expel ascospores into the
air, some of which eventually find flowering heads. C.
purpurea is a common floral parasite of commercial grains; the
Claviceps on smooth cordgrass may be a distinct species --
it is know to consistently produce a unique set of poisonous
alkaloids. See Raybould, A.F., A.J. Gray, & R.T. Clarke. 1998. The
long-term epidemic of Claviceps purpurea on Spartina
anglica in Poole Harbour: pattern of infection, effects on seed
production and role of Fusarium heterosporum. New Phytol.
138:497-505.