zine, antimony and other minerals have no effect; all perfumes stop it.

Passing in this flying review some of the lower forms of flowerless plants of forests and fields, with a few parasites on man and animals, only touching here and there an interesting and suggestive fact, we finally offer a word on those found upon our farm fixtures, houses, and especially all timber structures, although not confined to them alone, for even the wall, in the pride of its strength, crumblingly bows beneath their stealthy tread.

Builders have a woful knowledge of numerous fungi found on wood, e. g. the Polyporus destructor, truly as its specific name signifies, a destroyer; also P. thelephora, from a Greek word, meaning nipple, by reason of its teated surface; and P. sporothricum, from the little pore-tubes having hairy filaments hanging out; the one, however, most familiar to me from my earliest recollection is the Weeping Morel (Merulius lachrymans), a crying evil. Both this and the M. vastator are sufficiently devastating to all timbers in warm, moist situations where there is no free circulation of air, as in hollow trees, cellars, wainscoting, timbers of ships, sills, sleepers, etc. These invaders, little less than legion, all pass under one common designation, the dry rot.

Weeping morels at first appear in a white spot, or point, spreading their filaments flat over the surface of the timber in rounded white cottony patches from one to eight inches broad, and so onwards; near maturity it forms folds of yellow, orange or brown, weeping Madeira wine colored tears; they soon after mature myriads of dirty, rusty-colored sporules which spread destruction far and wide; wood, books and walls crumble in its consuming path; buildings often, though taken down and the stones scraped and fired, scarcely suffice to stay the scourge. Is this the leprosy of the wall spoken of in Leviticus? Heat applied to dry wood only hastens the malady. It can be forestalled by cutting the timber in winter when the sap is out; and, better still, by immersion in

water for a long time, to fully supplant or extract the entire juices, as is often practiced by the best ship-builders and honest wheelwrights, carpenters, etc., who regard a worthy and enduring reputation. It is said that the ships in the Crimea Sea suffered more from this insidious foe than from the ravages of fire, or the shots and shells of their enemies. We have seen samples of this light, crumbly, papery shelled wood, with its weight and strength totally consumed.

A strong wash of corrosive sublimate solution over the timbers of cellars on which these deliquescent or weeping morels so dampen it, are at once rendered dry, and the evil often entirely arrested in the midst of its havoc.

Lastly, most of us have heard, and many have no doubt seen, specimens purporting to be a caterpillar turned into a plant, or some such similar foolishness. We have one in the herbarium which any one may see at their leisure. This is one of those parasitic fungi, that rob and kill in order to supplant and live on others gains; the dying grub's head never sprouts up as a plant, but the seeds or spores of the Spheria Robertsii alight upon the caterpillar of a moth, the Hepialus, when it buries itself in the mossy woods to undergo metamorphosis, and by its growth destroys the napping grub. Two species of these are used by the Chinese, who sell them in bundles of eight or nine, with the worms attached, which they place in the stomach of a duck and roast for the patient to eat.

VARIATIONS OF SPECIES.

BY A. H. CURTISS.

IN the March number of the NATURALIST we observe an account of a remarkable growth of Bidens chrysanthemoides, and as the writer seems to fear that his story may be considered an exaggeration, we come to his support with one

twice as tall, which, happily, refers to the most nearly related species, Bidens cernua. While collecting along the alluvial, marshy borders of the Potomac below Alexandria, some years ago, we found this species (not before discovered so far south) growing to the extraordinary height of five feet. This, compared with Gray's maximum height, will be seen to be in the ratio of six to one; while in the instance of B. chrysanthemoides, it was only three and a half to one. Our press would barely admit of smaller branches, while in collecting the same species in New York, we have easily pressed two entire plants side by side. As if this were not a sufficiently surprising effort of nature, on proceeding some distance farther, we came upon some plants of Oxalis stricta (an eccentric plant in more than one respect) fully five feet in height, and widely branched. We do not apprehend that such statements will be discredited by any person familiar with the vegetation of such localities. We mention them as curiosities in vegetable growth, and not as matters worthy of permanent record, or of a place in a work of the nature of the "Manual."

Such variations in the size of plants appear to be seldom attended with any material change of specific characters, and are therefore of less interest than those produced by difference of latitude and longitude, or by change of station, as from wet to dry locations, from sunny exposures to shade, from marine to fresh-water localities, or from mountain to valley, and vice versa. These are all fertile in effects of the greatest interest to modern theorists, and no botanist should fail to make them a subject of special study. Such observations inevitably suggest a former unity of many of our species and genera, and result in the correction of too wide. distinctions. The two species of Bidens referred to, together with B. connata, are strongly suggestive of a common parentage; and when Bidens frondosa is compared with Coreopsis bidentoides (especially since the former has been found with upwardly barbed awns), it is difficult to perceive

a proper dividing line between the two genera. We do not anticipate a loss of the genus Bidens, however, though probably no collector would object to its thorough extermination from our flora, with all its "pitchforks" and "Spanish needles," together with the Desmodiums, which in autumn force the herborizer so extensively into their service in transporting their "fearfully and wonderfully made" legumes.

As examples of the manner in which one genus may merge into another, and one species into another, we cite two instances which have lately fallen under our observation. The first is that of the Gymnostichum Hystrix of Schreber. This remarkable grass was apparently separated from the Linnæan genus Elymus, upon the single character of the absence of glumes. In this section of the country, however, we find it with well developed glumes, which are persistent after the spikelets fall. The glumeless and intermediate forms also occur, but the one most common has rigid, awn-like glumes situated precisely as in Elymus, of nearly an inch in length, and with one prominent nerve, being therefore triangular, though appearing terete. We have never found the paleæ dentate (as figured in Pl. 11 of Gray's Manual) in any form of the species, and the "pedicels" are evidently the joints to which the glumes are attached, and are but little longer than in some species of Elymus. Were the spikelets appressed as in Elymus, it would strikingly resemble some species of the latter in aspect, and as there appears to remain no constant technical distinction of any importance, we see no reason why its former name, Elymus Hystrix L., should not be restored.

Our second case is that of Eupatorium aromaticum L., which we are convinced is but a variety of E. ageratoides L. The latter species is very common at the North in low, rich woodlands, and has large, thin and smooth leaves, which, we think, vary very little in size and shape. On reaching Maryland (except in the mountains) and the coast this species seems to be supplanted by one having the same peculiar flower-heads, but lower and less branching, with

smaller corymbs, and smaller, thicker and pubescent leaves. This species is common in Virginia in dry copses and open woodlands, but varies greatly, so that we are puzzled in selecting typical specimens. On coming to the Piedmont region, however, the problem was soon solved, for here we found that it was no longer confined to dry and somewhat exposed and sterile situations, and that in proportion to the degree of shade or richness and dampness of soil in which it grew, so the leaves became thinner and larger, and the whole plant more robust, till it could no longer be distinguished from the true E. ageratoides; and on visiting the neighboring mountains, we found the latter species growing in great abundance. If, therefore, the generally accepted rule be applied to this case, E. aromaticum must be considered to be a variety of E. ageratoides. In a very similar manner Acalypha gracilens Gray, varies into A. Virginica L., and it has very properly been reduced to the condition of a variety by Professor Gray. In this connection we would mention that we have found Eupatorium aromaticum with leaves beautifully whorled in threes. As the same arrangement has been observed in another species, it would seem that the genus is inclined towards this mode of leaf-arrangement, which makes that of E. purpureum appear less anomalous.

Before closing we would add to the list of monoecious and dicecious plants which have been found with androgynous inflorescence (see March number of the NATURALIST, p. 46) an instance of the same mode of inflorescence in Fraxinus Americana. In the spring of 1867 we observed in this county (Bedford Co., Va.) a tree of this species with panicles thoroughly androgynous; but in this instance, as if a violence had been done to nature, every flower afterwards became changed to a mass of small, contorted leaves, bending the branches with their weight, and presenting a truly remarkable appearance.

NOTE, - Bidens cernua and B. chrysanthemoides might also have been adduced as species which run together. We beg for a sight of these tall Virginian specimens.-A.G.