416 Agricultural Journal of Victoria. 



decaying material wliicli has otherwise been prepared for it. In fact 

 there are many snch fungi known which are therefore called sapro- 

 2')hytes, and in order to settle conclusively that a fungus is a parasite, 

 that it preys upon the living plant and causes its decay, there must 

 be infection experiments carried out, and the disease produced in the 

 plant through the agency of the fungus supposed to be concerned. 



With this object in view, a series of infection experiments was 

 designed and carried out by my assistant, Mr. Robinson. As each 

 batch of specimens was received, they were carefully examined, and 

 the stubble from a proportion of them was placed in sand in ordinary 

 flower-pots, and clean, healthy wheat of the previous year sown with it. 

 After eighteen days, when the wheat-plants were about six inches high, 

 characteristic brownish spots were observed on the young stems. 

 Microscopical examination showed the presence in abundance of the 

 young mycelium of the Ophioholus^ not only in the sheath and stem, 

 but also sometimes in the roots, where the same discoloration was 

 often observed. After six weeks many of the plants were dead and 

 showed in abundance mycelium identical with that in Figs. 3, 5, 

 6, 7 and 8. Extended experiments and observations are needed 

 here, and will take some time to thoroughly carry out, though it 

 may be said that the work has proceeded so far now that no difficulty 

 is anticipated in being able to raise take-all plants with the fruit of the 

 fungus Opjhioholus upon them from these pots. The plants in the check 

 pots sown in uninfected sand, remained perfectly healthy in appearance. 



* Ophiobolus gratninis, Sacc. 



Perithecia gregarious or scattered, slightly erumpent or immersed, smooth and 

 covered with numerous septate branching hyphae, globose, with straight, oblique or 

 slightly curved beak, membranaceous to carbonaceous, \'ery large, body 200 — 400 

 microns, f and neck up to 200 microns long. 



Asci straight or slightly curved, elongated clavate, rounded at apex, subsessile, 

 8-spored, 90-130x11-13 microns; paraphyses slender, septate, attenuated towards 

 apex, longer than asci. 



Sporidia sub-hyaline, fasciculate, slightly curved, usually blunt at one end and 

 acute at the other, slender, at first 3-5 septate, often at length 8-9 septate and promi- 

 nently guttulate, 70-105x3 microns. 



At base of stem and on roots of Wheat. 



Hendcrsonia graminis, ii.sp. 



Perithecia black, punctiform, erumpent, globose with projecting neck and covered 

 with fuligintus, simple, septate, hyphae, more particularly on neck, dark-brown by 

 transmitted light, membranaceous to carbonaceous, of parenchymatous texture, about 

 240-360 microns diam and neck up to 200 microns long, and occasionally branching. 



Sporules dark-olivaceous in mass, pale olivaceous individually, straight or slightly 

 curved, fusiform and acute at both ends, or blunt at one end, 7-septate when mature, 

 not constricted at septa, with granular contents, 32-38x4-5 microns, very commonly 

 35 microns long. 



At base of stem and on roots of Wheat. 



The perithecium is rather variable in its nature. It may or may not be provided 

 with a beak, and it may be covered all over with projecting hyphae or only partially, 

 sometimes on the neck and sometimes only at the base. 



This appears to be the pycnidial stage of Ophwbolus graminis, Sacc, and although 

 the perithecium is often provided with a beak, still it is also often without, and I have 

 accordingly retained it in the genus Hendfrsonia In 0. herpotricJius (Ft.) Sacc, closely 

 allied to this species there is also a pycnidial stage, Hcndersonia Jierpotricha Sacc. , in 

 which the spores are cylindrical, 8-septate and 36x6 microns. 



f Micron is approximately t^sIq^ of an inch. 



