'iiy Agricultural Journal of Victoria. 



germinate in water very readily when the temperature is favourable, 

 and give rise to long germ-tubes or little sickle-shaped bodies. (Figs. 

 17 and 18, x 400). During November the spores germinate easily in 

 water in from one to four days, either producing the sickle-shaped 

 bodies directly or giving rise to a longer or shorter septate or non- 

 septate germ-tube, which may or may not bear a rosette of these 

 short, sickle-shaped l)odies at the end. Mangin (17) observed the 

 germination of these latter by sowing them in the young plantlets of 

 wheat in a humid atmosphere. At the end of four days he found that 

 they had put forth a germ-tube at one end, which crept along the 

 surface of the root-hairs and soon pierced the membrane and entered 

 the interior of the plant. In water to which certain mineral salts 

 were added, such as 1 per cent, sulphate of ammonia and 1 per cent, 

 phosphate of ammonia, germination did not take place. 



Associated with the Ophioholus another fungus was occasionally 

 found, which usually produces its fructification a little higher up the 

 stem, although it may be intermixed with it and even occur on the 

 roots. The perithecia or spore-cases were very similar, but the 

 contents were quite different. Instead of containing a number of 

 little sacs, the spores were free, and a little darker in colour, and only 

 about one-half or one-third the length of the others. When the ripe 

 perithecia are placed in water, the spores escape, and are held together 

 by a mucilaginous substance, which soon dissolves in the water. The 

 spores germinate very rapidly when ripe, by putting forth from one 

 or more of the joints, long and branching threads, which probably 

 enter the young roots or root-hairs of the plant, and become parasitic. 

 At first sight it might seem as if there were two distinct fungi con- 

 cerned, but they are very probably, as in the case of allied species, 

 only different stages of the one fungus. Whether this is so or not, 

 the Ophioholus or wheat-stem-killer was always present, and the 

 other form only occasionally. 



The Wheat-stem-killing Fungus in Australia. 



The fully mature or reproductive state of this fungus was first 

 found by me in December, 1900, on wheat sent from South Australia 

 by the then (Tcneral Secretary to the Agricultural Bureau, Mr. 

 Molineux. In the accompanying letter he wrote : — "I am forwarding, 

 under separate cover, samples of wheat affected in some way unknown 

 to me. The farmer who grew it, states that a few plants here and 

 there in the crop go off rather suddenly, the head colors, but there is 

 no grain in it. Frost, hot winds, and poverty of the soil cannot be 

 blamed. The crop was manured with a mixtui^e of (>0 lbs. mineral 

 superphosphate, and 20 lbs. bone dust per acre. The trouble is worst 

 in the heavier crops ; those only light are comparatively free. On 

 some adjoining farms the trouble appears on well-worked fallow and 

 fresh ploughed land, on land manured with superphosphate or bone- 

 dust, and land not manured." This is the disease known as white- 

 heads, and the above description fairly represents the varied con- 

 ditions under which it occurs. A brief account appeared in the 



