THIELAVIOPSIS PARADOX A. 537 



de Seynes' Stys3,nus-like Fructification. 



The groups of conidiophores seen by de Seynes (3) and 

 likened by him to the conidiophores of a Stysanus have not 

 been recorded by any subsequent writer, though they are 

 of quite common occurrence. On natural substrata, e.g., 

 diseased coconut and sugar cane, they occur when the culti- 

 vation is old, that is, after the micro- and macro-conidia have 

 been produced, and tlie substratum is becoming rather dry. 

 Similarly, they frequently occur on sugar-agar plates, when 

 the culture is old and drying. An almost certain way of 

 obtaining them is as follows : a drop of sugar cane extract 

 placed on a sterilized glass slip is inoculated with Thielaviopsis 

 spores and kept in a damp chamber ; after a few days (two or 

 three) the mycehum, which is now producing micro- and 

 macro-conidia in abundance, runs from the drop over the shde in 

 more or less radiating strands ; the Stysarms-Uke fructification 

 is then produced along these strands. 



The foundation of these fructification is formed by a small 

 plate of interwoven hyphse, or by a number of hyphse running 

 parallel and close together, so as to form a strand. From a 

 point on such a strand, or from the plate of hyphse, a number 

 of microconidiophores arise side by side and adhere to one 

 another, thus forming an erect stalk from 1 to 3 mm. high and 

 from 0-08 to 0*25 mm. in diameter. These extrude conidia 

 in the usual way, but the conidia remain in a globule at the 

 top of the " stalk." The stalk rapidly turns black, but the 

 mass of conidia remains white much longer than the micro- 

 conidia do in hanging drops ; eventually, however, the mass 

 darkens. The whole structure, pseudo-stalk and globose head 

 of spores, superficially resembles a Stilbum, or a ripe Sphcero- 

 nema ; I have referred to it elsewhere as the " Sphaeronemoid " 

 stage, before I was aware that it had been noted by de Seynes. 

 On sowing the spores in sugar cane extract, their identity with 

 the normally-produced microconidia is fully estabhshed. 



This form is produced if the spores are placed on pieces of 

 filter paper, which are floated on the surface of a nutrient 

 solution. From this and the other instances given above it 

 would appear that it is some way dependent upon the water 

 supply, being produced when this is diminishing or not readily 



