Colonies on cornmeal agar without a special pattern. Main hyphae up to 8 μm wide. Appressoria clavate, knob-like or sickle-shaped, usually formed in clusters. Sporangia terminal or intercalary, filamentous, consisting of undifferentiated and inflated lobulate or digitate elements of variable length. Zoospores formed at 25-30℃. Encysted zoospores 10-12 μm diam. Oogonia terminal or intercalary, globose, 26-32 μm diam. Antheridia 3-6 per oogonium, stalks branched, often more or less loosely enveloping the oogonium, diclinous, occasionally monoclinous, originating at various distances below the oogonium. Oospores aplerotic, about 20-27 μm diam, wall up to 2 μm thick.
Specimens：
Taiwan, Nantou: ginger, 28 May 1997, Pm-1; 14 Jul 1997, Pm-2, Pm-6. Taiwan, Taichung: tomato, 03 Jul 1997, Pm-1. Taiwan, Jhongli: Lettuce, 12 Oct 1997, Pm-3-r5. Taiwan, Taipei: soil in Calla lily (Arum lily) field of Yangmingshan National Park, Sep 1997, Pm-10.
Habitat：
soil, water, plant
Distribution：
Taiwan, USA, Africa, Papua-New Guinea, India, Japan, Brazil, Netherlands.
References：
Plaats-Niterink, AJ van der. 1981.
Provided：
P. H. Wang
Note：
The high maximum temperature is typical of P. myriotylum, only a few of the species in the group with inflated filamentous sporangia can grow at 40℃, viz P. aphanidermatum and P. deliense, but these species differ from P. myriotylum by their intercalary antheridia and only one antheridium to per oogonium. P. myriotylum can be pathogenic to several plants, especially at higher temperatures.
Phylum：Oomycota >> Class： Oomycetes >> Order： Pythiales 
BCRC Number：