The genus is characterised by the cap being dry (rather than slimy as in Suillus), never with a ring around the stalk, and the spore print olivaceous when fresh.

There are three indigenous species, all endemic, plus one introduced. The indigenous species are all associated with tea-tree. The introduced B. edulis is associated with oaks at a few South Island localities.

The native species are ectomycorrhizal on beech and tea-tree. The introduced B. edulis is known from under oaks at a few South Island localities.

The genus is characterised by the flesh and/or pores often having yellow colours, and the flesh often turning blue with damage. Spore print olivaceous when fresh.

Six species have been reported from New Zealand, only those listed below have descriptions or images available from NZFungi.

Secotioid genus related to the boletes, with a single species, endemic to New Zealand.

The white fruiting bodies with a short stalk are always found under tea-tree, and it is quite common in northern New Zealand. Mycorrhizal.

A single species in an endemic genus.

Common in the north of New Zealand on soil under manuka and kanuka.