RESEARCHES INTO THE OOSPORES OF
SOME FUNGI.

By the Rev. J. E. VIZE, M.A., F.R.M.S., &c.

A CONTROVERSY so hot and strong has long been going on about the resting spores of Peronospora infestans, that these atoms in creation have assumed a gigantic proportion. With this idea in mind I have, during the past season, been paying attention to the resting spores of various plants, besides those of the potatoe disease, and shall hope to work at them as opportunities offer. Except with the genus Cystopus they are not very easily found, which circumstance arises, I imagine, from the fact that Cystopus develops its oospores very soon after its conidia are visible, whilst Peronospora does not, at all events not so transparently as the other genus, nor is their locality so easily ascertained.

I will proceed at once with those species in Peronospora which I have detected.

With regard to Peronospora Schleideniana (De By.). I remembered last summer having obtained some onions with this fungus in the acrospore state, and therefore determined to go and obtain, if possible, some specimens to examine for the resting spore. Fortunately, the garden was as a rule neglected, so much so indeed, that the onions, to my great relief, had not been disturbed. I found them in every state, from healthy onions to very rotten ones. Taking them home for examination, I saw a great number of the ubiquitous Sphæria herbarum, and after much search, especially in the most decayed portions, found, very sparingly scattered indeed amongst the material, a few genuine oospores. All traces of the raphides of the onion had gone—so had all the chlorophyll; the oospores were in the brown putrid magma, composed, I believe, of the oil cells of onion. That I expected to meet with a good deal of trouble in getting the oospores was a fact, because the Peronospora in its summer state was very scarce in the onion bed. One thing struck me as being singular, namely, the small size of the oospore compared with the large size of the acrospore, which is the largest acrospore I know. The date on which the winter spore was found by me was the 29th of February.

My opinion as to the rarity of meeting with the oospore of this fungus was confirmed by the fact, that towards the end of August this year, I could not find any trace of the same in the decayed leaves, although some weeks previously they had been prolific in the acrospores.

Whilst searching for the Onion Peronospora, I recollected that the same garden had grown a plentiful crop of Peronospora gangliformis on lettuce. The dead stems were lying on the ground, and when I looked for the oospores they were to be found in immense numbers. Their exact place was very regularly marked. The stem of the lettuce plants I cut up with a knife. In its interior are parallel columns of spiral vessels, forming very beautiful objects for the micro

scope. Directly under these spirals, and between them and the outward cuticle of the plant, the oospores abounded; there was no difficulty in procuring them, they were unmistakable, and were as numerous, comparatively, as the Onion oospores were scarce. I was glad to obtain these, having heard some years since that they had only been found on Groundsel. On Groundsel I had found them with comparative ease during the previous autumn, in a neglected potatoe bed.

The oospores of Peronospora parasitica (Tul.) I found in enormous numbers in the decaying stumps of cabbages in my garden. Our friend, Mr. W. G. Smith, sent me some turnips which were supposed to have them in great abundance, even as he had himself found them. In those which reached me I could not find one, although I spent some two or three hours at them. Knowing, however, that Turnips and Cabbages were both of the Order Crucifero, I went to my cabbage plants, and found on living cabbages sparingly scattered, in the conidial form, the Peronospora, whilst on those whose heads were consumed for table, and whose stumps remained in the ground and were rotting, the oospore was most abundant, but nowhere except in the most putrid spots, which could be detected by a yellow colour. That these were the vegetable resting spores seems to me settled, from their exact correspondence with De Bary's figures, and also because I could not detect on the living cabbages any other species of the order Mucedines. Their locality corresponded very much with P. gangliformis.

Knowing that the Peronospora on the Ranunculus was to be had in several spots, I watched very carefully for the oospores of it, and after several gatherings of leaves infected with the acrospores, was fortunate enough to obtain some resting spores, on the 29th of April. My suspicions of their being likely to be found on the leaves of the Ranunculus itself were obtained from the fact, that a leaf of some unknown plant had been sent to me the previous year full of resting spores ; the leaf was very dead, dry, and brown. This leaf was a clue to my finding the spores of Peronospora ficaria, for I took home with me, on the above date, some decaying leaves, and on one or two of them the oospores were visible. One thing was essential to their presence, namely, the decay of the stalk bearing the leaf. Unless this were dying, and for a little distance downwards were brown from death, not an oospore could be discovered. I anticipate, after realizing this fact, that there will be no great difficulty in getting the resting spores of other plants in a similar way.

Mr. Phillips was fortunate enough lately to find Peronospora alta (Fckl.), for the first time on record, I believe, in England. I had searched over and over again unsuccessfully for it, and am satisfied that I have found plants infected with it, but which, owing to the locality not being suitable for developing it, would not grow it. This Peronospora grows on plantain, a plant which takes to itself an unusual time in drying, as is known by its local title of "Jack set the rick on fire," because the moisture in the leaf does not escape, and therefore ferments, and ultimately, if very abundant, burns the rick. In one or two leaves sent to me there are some very dark spots, which I feel sure contain the oospores; as yet they are not ripe enough to be seen under the microscope. I have little doubt that they will be discovered there by and bye.

Peronospora arenaria (De By), which, though considered rare, seems to be locally plentiful, has too succulent a host plant to let the resting spores be easily discovered. I tried to produce some artificially, but to no purpose.

Other species I have endeavoured to get, but signally failed—failed, probably, to make me persevere all the more in working to find them.

Since the above was written I have examined Professor Farlow's paper on the Enumeration of the Peronospore of the United States. He gives descriptions of 26 species of Peronospora with the oospores of all of them, naming their measurements. He then gives five more species, as "species whose oospores are unknown." P. sordida (Berk.) and P. sparsa (Berk.) are however the only two British ones enumerated in these five.

Cystopus spinulosus (De By.) is a plant recorded, to the best of my knowledge, only in Norfolk, and in the neighbourhood where I live. I imagine it is tolerably frequent, however, judging by the abundance of it when it is found at Forden. It grows on the common thistle by the sides of the high road, close to the grassy banks where the grass and the road unite, but the most prolific spot of all is where the stones are cast which are to be used for repairing the road. I have noticed year after year how very favourable to the luxuriance and development of the Cystopus this sort of place is. The conidia, when once found, are a tolerably sure clue to the oospores, for the conidia retain their place as a centre, and as they ripen the mycelium extends from them into the parent host on all sides. The result of this is, that the nourishment of the thistle in that place is absorbed by the fungus, which thus finds a suitable nidus for its oospores. A brown patch on the decaying leaf of thistle is an almost sure index to the resting spores, and of course the more lifeless the leaf looks the surer of success the searcher for the oospores will be. The oospores are so fine, and so large, that by soaking in water for a short time they can be seen with an ordinary pocket lens in situ. It took me some time to find these plants in the oospore state last August, but when once discovered they are easy enough to find afterwards.

Cystopus cubicus (Str.) I have had no opportunity of examining alive. Cystopus candidus (Lev.) seems to follow a similar life history in developing its winter state that C. spinulosus does. I believe, however, that when it grows on certain plants, horse-radish, for instance, the tissue of the host plant is so thin, that the ripening of the oospores takes place considerably on the ground, and therefore is not so easy to find. You can easily see, even in a few days, what ravages the fungus has made in the conidial state by the holes formed in the horse-radish itself. On Shepherd's Purse the oospores are much more easily traced than in the above plant, owing to the thickness of the plant on which they mature. Cystopus lepigoni (De By.) has recently been sent to me by Mr. Plowright. The oospores are plainly enough to be seen, but will be much better as to ripeness in a short time.

By M. C. COOKE, L.L.D., M.A., F.L.S., &c., &c.

THE subject selected for this paper belongs to an unfortunate class, for it is liable to fail in two directions. Either the verdict may be that there is nothing in it, for everybody may have seen specimens as big. Or, on the other hand, if they have not, or fancy they have not, then the whole thing will be condemned at once as an exaggeration. In order to avoid the latter, which I consider the worse alternative, I have been careful to include nothing, on my own authority, which has not been measured carefully, and in most cases drawn to measurement. Species inserted on the authority of others, are supported by quoting the authority. If there is " nothing in it" that will not be a novelty sufficient to occasion surprise. Agaricus (Amanita) virosus, Fr.

Fries says that the stem in this species is from 4 to 6 inches long, and the pileus from 3 to inches broad. I have never found it but once, and then three or four specimens were growing together in a plantation near Bungay.

The largest

of these was 10 inches high, stem 13 inches thick at the base, and the expanded pileus had a diameter of 7 inches. In grandeur of appearance and pungency of odour it was a species never to be forgotten. Although found in August of 1865, its memory is not obliterated, but revived whenever a good juicy Phallus presents itself. Filtered through the mists of twenty years this odour is not sweetened yet, and probably will remain, not "too much beautiful, for ever. Agaricus (Amanita) excelsus, Fr.

Fries gives as the dimensions of this species, "stem 4 to 6 inches long, pileus 4 to 5 inches broad." Two specimens found by us near Watford in 1883 considerably exceeded these dimensions, one of them being 10 inches high with a diameter of 7 inches. The base of the stem was 2 inches thick.

Agaricus (Lepiota) procerus, Scop.

It is very probable that this species will attain a considerable size under favourable conditions, as its growth is undoubtedly rapid. The Monographia states that it will reach 4 to 8 inches or more in diameter of pileus, and Berkeley says from 3 to 7 inches broad with a stem from 8 to 12 inches high. One specimen obtained in Kew Gardens on the 16th October, 1883, was nearly 10 inches high, with a pileus of upwards of 7 inches diameter. This really deserved the name of "Parasol" mushroom, but it has been exceeded, for I measured on one occasion an old pileus, going to decay, of which the stem could nowhere be seen, and it was a little over 8 inches in diameter. Specimens more than 6 inches are not uncommon amongst the undisturbed masses of dead leaves in some sheltered nooks of the grounds attached to Kew Gardens.

Agaricus (Lep.) rachodes, Vitt.

Mr. W. G. Smith records specimen from Wilton, October 12th, 1884, exactly 10 inches high.

Agaricus (Armillaria) melleus, Flor. Dan.

Although this is an exceedingly variable species, I find no records of its attniaing any extreme size, beyond the intimation by the Rev. M. J. Berkeley that it attains a diameter of 7 inches with a stem 8 inches long. Fries stated 6 inches as the extreme diameter. In 1861 I found specimens at the foot of an elm 6 inches in diameter at Hampstead, and at Watford, two years ago, I collected specimens exceeding this by an inch, but the stem, although nearly an inch thick, was not so long as the diameter of the pileus. The species is so common, and mycologists usually treat it with such contempt, that they do not take the trouble to measure specimens, hardly to look at them, save to warrant the exclamation "Bah! its only melleus!"

Agaricus (Armillaria) mucidus, Fr.

I have preserved no record of dimensions attained by this species from my own knowledge; Berkeley gives 1 inches as the usual diameter of the pileus, with a stem of 3 inches, but this is certainly far below the maximum. Dr. Bull has figured the section of a specimen quite 7 inches in diameter, with a stem nearly as long. It is by no means unusual for it to exceed about 4 inches, which appears to be something like the maximum of ordinary specimens. One extenuating circumstance may be urged in favour of this species, which is analogous amongst Agarics to the Bream amongst fishes, for its sliminess, that it is a most delicate species when prepared for the table, and here the analogy with the "Bream" ceases. Agaricus (Tricholoma) nudus, Bull.

According to Berkeley this species should have a pileus of about 2 inches in diameter, with a stem 2 inches high and from 3 to 4 inches thick, whilst Fries allows a diameter of 3 inches for the pileus, and 3 inches for the length of the stem, with a diameter of half an inch. During the month of November, 1881, large masses of this species were found in two or three localities in the Pleasure Grounds, and Queen's Cottage Grounds, of Kew Gardens. Many of the specimens, at least 20 or 30, were 5 inches in height, with a thickness of stem at the base of from 1 to 2 inches, the expanded pileus varied from 5 to 6 inches in diameter. The stems were of a beautiful violet colour, but the pileus of a bright rufous. Even these large specimens were firm and sound, and when cooked were quite equal to, perhaps rather better than the smaller forms. It is one of the medium-sized specimens which is figured on plate 133 of the Illustrations.

Agaricus (Clitocybe) nebularis, Batsch.

I should hesitate to limit the capabilities of this species, it certainly is " one of great capabilities," although the pileus is limited by Fries to a diameter of 3 to 5 inches, with a stem of 3 in length, and an inch in diameter. In October, 1861, I met with a colony large enough to fill a full-sized wheelbarrow, growing upon dead leaves at Dufferin Lodge, Highgate. Amongst these were at least 20 specimens not less than 7 inches in diameter of pileus with stems 4 inches long, and 14 inch in thickness. Since then I have seen them nearly as large in the Pleasure Grounds at Kew. Six inches is not by any means an uncommon diameter for sound, and uninhabited specimens. I have found them growing in precisely the same spot for several years in succession, and it is in such established localities