Phragmidium bulbosum  

Spermogonia 25–30 μm µm diam., epiphyllous, in minute groups opposite the aecia, becoming fused, subcuticular.
Aecia to 1 mm diam., hypophyllous, caeomoid, circular or annulate, orange, paraphysate. Aeciospores 17–21 μm diam., globose to broadly ellipsoidal, the wall hyaline, coarsely verrucose with broad shallow warts to 3 μm diam., 1·5–2 μm thick; pores obscure.
Uredinia  0·1–0·3 mm diam., hypophyllous, irregularly scattered without spots or on small reddish, yellowish, brownish or purplish spots or occasionally on larger purplish blotches, yellowish, paraphysate. Urediniospores 19–24 × 16–18 μm, obovoid to ellipsoidal, the wall hyaline, echinulate, the spines 1–2 μm apart, ca 0·5 μm high, 1–2 μm thick; pores 2·5–4 μm diam., rather obscure; paraphyses cylindric-clavate, incurved, 40–60 × 8–13 μm, the wall thickened to 2–3 μm at the apex.
Telia similar to the uredinia but black. Teliospores cylindrical, not constricted at the septa, the apex rounded and with a blunt apiculus to 13 (–19) µm long and 5–7 μm diam., 4- to 7-celled, dimensions excluding the apiculus: 4-celled spores (59–) 65–68 (–71) × (30–) 32–35 (–37) μm, 5-celled spores (73–) 78–83 (–89) × (32–) 35 (–37) μm, 6-celled spores (86–) 91–98 (–104) × (32–) 34–35 (–37) μm, 7-celled spores (98–) 104 (–111) × (32–) 33–34 (–36) μm; wall sienna to dark umber brown, coarsely warted, 4–5 μm thick; pores 2–4 in each cell; pedicels 75–160 long, 7–10 μm wide at the neck, swollen below to 13–19 μm diam.

Description adapted from Laundon & Rainbow (1969).