During the month of September, 1864, it was our good fortune to spend a week in revisiting the scenes of our boyhood, and exploring the minute botany of one of the marshy districts of East Norfolk. One day of the seven, memorable to us for the discovery of three specimens of a large Boletus (_B. cyanescens_),[7] not found, to our knowledge, since the days of Sibthorpe, was further enriched by a species of _Trichobasis_, new to Britain, and apparently uncommon on the Continent. This rust was found on the leaves of the “grass of Parnassus” (_Parnassia palustris_) on a narrow strip of marsh near Irstead church. It was sought in vain elsewhere. The leaves were scarcely changed in appearance, except by the presence of the pustules. There were no discoloured spots, but the pustules appeared sometimes plentifully, more often scattered, on both surfaces of the leaves: they were small, of a bright brown, with oval spores; the latter were, in their early stages, shortly stalked. We have called this species _Trichobasis Parnassiæ_. It is possibly the same as published by Westendorp in his “Herbier Cryptogamique Belge” as _Uredo Parnassiæ_, but we know of no copy which we can consult, and have failed in discovering any other species to which we can refer it. It is certainly a _Trichobasis_ and not an _Uredo_, according to the present limitation of the latter genus. Footnote 7: Two of these specimens were found at the bottom of a hedge-bank, amongst grass, by the side of the road leading from Neatishead-street to Irstead Rectory, and the third in a similar position by the Norwich road, two hundred yards from the turning which leads to Neatishead-street.