Figure 1.

(a–c) Colonies of alder phytophthoras. (a) Swedish variant, showing chimeric white fertile patches. (b) Standard alder Phytophthora with typical appressed colony. (c) Dutch variant, showing irregular fertile sectors. (d–f) Gametangial types. (d) Swedish variant showing smooth oogonium (above) and two-celled amphigynous antheridium (arrowed). (e) Standard alder Phytophthora, showing P. cambivora-like ornamented oogonium and two-celled amphigynous antheridium. (f) Netherlands variant showing extremely ornamented oogonium. (g–j) Diverse gametangial types representative of four different, single hyphal-tip subcultures from U.K. variant P841, including oogonium with paragynous antheridium (g, arrowed) and highly coralloid oogonium (h). (Bar = ≈10 mm.)