DISEASES CAUSED BY FUNGI 31 



Peglion, resembling Species D of the writer, was obtained from 

 a diseased hazel nut in Italy in 1901, and appears to have been 

 seen in France in association with the previous species. Nemato- 

 spora Lycopersici Schneider, described in 1917 from fruits of 

 tomato supposed to have come from Cuba or Mexico appears 

 to differ only in the recorded measurements. 



Four species have been met with in the West Indies, two of which remain 

 as yet unnamed. In species A, B, and C, the mycelium is hyaline, fine to 

 coarse, non-septate except in connection with reproduction, and branching 

 almost entirely by regular dichotomy. In cultures small bud-like pro- 

 jections may occur along the course of the hyphae. In Species D (Nema- 

 tospora) the thallus as developed in fruits and vigorous cultures is typically 

 yeast-like, and consists of a mixture of two forms : (i) toruloid cells and 

 cell-groups, the units of which are very variable in form but generally 

 elliptical or ovate, (2) much larger spherical cells, single or attached in 

 small groups. In old cultures or when growing in tap-water, a mycelium 

 is produced which is made up of long, sparingly branched and very sparingly 

 septate hyphs (Fig. 7). 



The spores develop in sporangia which in the three typically hyphal 

 species are expansions of a terminal or intercalary section of a hypha. 

 In the fourth species they are formed from a single cell which separates 

 from the yeast-like thallus, by the lateral expansion of a hypha in the 

 hyphal form, or by direct outgrowth from a germinating spore. The 

 spores are set free in all the species by solution of the sporangium wall. 



The spores of Species A are unicellular, falcate, measuring 18-21 

 microns : on the convex side they are provided with a thickened rib 

 which extends from about the middle to one end, where it projects in 

 a fine point. They are formed in large numbers in the sporangium, with- 

 out any appearance of regular arrangement (Fig. 4). The spores of 

 Species B are acicular, rather blunt at one end, sharp at the other, and 

 measure 13.5 microns. They are formed in two equal opposed conical 

 bundles, their broad ends interlocking (Fig. 5). 



In Species C and D the spores are alike in form and occurrence. They 

 are spindle-shaped, produced at one end into a long thread-like appendage, 

 and have a slight projection on one side near the middle. They are formed 

 in two equal opposed bundles in eachsporangium, joinedby a thread formed 

 of their combined appendages. The number on each side varies from one to 

 ten or more. The two bundles are usually rather widely separated, but 

 have been seen to overlap and in extreme cases lie side by side. Occasion- 

 ally a single bundle is formed occupying the whole of a small sporangium. 

 The measurements obtained of the spore body, without the appendages, 

 have been 27-35 X 2 in C, 30-40 x 2-3 in D. 



Germination in Species A is by an ordinary germ-tube generally 

 developed about the middle ; in B, C, and D it is preceded by the formation 

 of a spherical swelling, from which are produced one or two germ-tubes, 

 or in C and D several short beaded rows of cells which may set up yeast- 

 like budding. In the last three species the contents of the spore show, 

 from a division near the middle, a difference in refraction and in taking 

 up stains, but the existence of a septum cannot be detected. 



These fungi have been found in no other situation than in 

 fruits and seeds, and in the writer's experience infections have 

 always been associated with bug punctures. A list of the plants 

 on which infections have been found is given below, and there 

 is no doubt that the number could readily be largely increased. 



The effect on seeds is the production of brown or white 



