The gelatinous, generally reddish-brown masses of spores - the teleutospores - formed on the juniper in the spring germinate and form minute spores - sporidia - which give rise to the aecidium stage on the pear.
There are, in addition, various other forms (Seroand Exo-sporidia), also primitive in character, but which are as yet too insufficiently known for it to be certain whether they are of distinct ordinal rank, or should be placed with the Haplosporidia.
Forms with septate thallus, and reproduction by chlamydospores which on germination produce sporidia; sexuality doubtful.
D, The sporidia: in B the sporidia have coalesced in pairs at v.
The teleutospore, with the sporidia which arise from it, is always present, and the division into genera is based chiefly on vulgaris, with a, aecidium fruits, p, peridium, and sp, spermogonia.