Rust fungi on Annonaceae: the genus Sphaerophragmium

Seven species of the rust genus Sphaerophragmiumoccur on members of the tropical plant family Annonaceae. Uropyxis gerstneriis recombined to S. gerstneri. A new species, S. xylopiae, is described from Xylopia acutiflora. The host plant of S. boanenseis identified as Mitrellasp. Sphaerophragmium pulchrumis transferred to Dicheirinia. The anatomy of telia with teliospores and parasitizing mycelium is described and illustrated in detail. A new type of M-haustorium, which emanates laterally from intracellular hypha, is detected in S. monodorae. An identification key is given.