The boletes of Michigan, by Alexander H. Smith and Harry D. Thiers.

GASTROBOLETUS 397
to pleurocystidia. Tube trama bilateral, with a distinct medial layer composed of hyaline subgelatinous hyphae. Pileus trichodermium of loosely
interwoven, septate, pale brown hyphae 3-6 u wide, some with slightly
swollen end-cells. Clamp connections absent.
Habit, habitat, and distribution.-Gregarious on sandy soil in a
second-growth oak-hickory forest, south of Otis Lake, Barry County,
September 1, 1966.
Observations.-This species is obviously closely related to the genus
Leccinum. However, because of the gastroid hymenophore and the fact
that the tubes are arranged so that spores cannot fall out of them, it
was described in Gastroboletus.