Appendages on the Spores of Myrothecium verrucaria

Abstract

DURING an investigation on the degradation of cotton by Myrothecium verrucaria it was observed that spores produced by cultures of this fungus showed under the microscope an unexpected appendage or ‘tails’ which is illustrated by Fig. 1, and which, to our knowledge, has not been described previously. This appendage cannot be seen when unstained spores mounted in water are examined under the microscope by ordinary illumination. It is not stained by cotton blue, but is coloured pink with Loeffler's flagella stain and is then clearly visible. When a drop of a spore suspension in water was placed on a microscope slide and allowed to evaporate, it was observed, by phase contrast illumination, that the spores, which had ‘tails’, stuck to that part of the slide from which the water had receded whereas other spores, which appeared to have no ‘tails’, were carried along by the receding water. An electron micrograph confirmed the existence of the ‘tails’, suggesting that they are extremely thin, and fan-shaped. Furthermore, it appeared that the ‘tail’ emerged just to one side of the point of the spore, not from the point itself. From the observations we think it possible that, in water, the appendage might have a conical shape.