Definition: A genus of pathogenic fungi causing dermatophytosis in humans and animals; species may be anthropophilic, zoophilic, or geophilic, and attack the hair, skin, and nails, and are characterized by their growth in hair. Endothrix species grow from the skin into the hair follicle, penetrate the shaft, and grow into it, producing rows of arthroconidia as the hyphae septate; there is no growth on the external surface of the shaft. Ectothrix species are of two kinds, large spored and small spored. In both, the fungus grows into the hair follicle, surrounds the hair shaft, and penetrates it, but continues to grow both within and outside the hair shaft, producing arthroconidia externally.
[tricho- + G. phyton, plant]