boilers extending to the bank against which the structure stands. When the convenience of a bank or hill cannot be had, it is evident that both the boilers and oven might be placed on or near the ground, if the chimney were sufficiently high, (not less than seventy feet,) and the walls built so as to be free from crevices. Fig. 3.

W

The boilers are supported upon large iron beams, (partly shown below r,) between which arches are turned in their longitudinal direction. There are several doors in the position of x, to allow the flues to be cleared from ashes, &c. These doors open into the arches beneath, and there are others along the sides for the same purpose. The boilers are usually placed in contact with the oven; but the passage y (which extends to the chimneys) is proposed to be left to turn more or less of the flame into the chimneys, which will place the relative distribution of the heat to the oven and boilers under control, a point which seems not to have been hitherto attained. This might also be accomplished by separate chimneys to the oven and boilers. In either case, the chimneys must be supplied with a damper, which is best placed upon the top.

If four simple boilers were used, the flame might be passed under one pair and return under the other; or, the oven might be placed upon the bank, which would afford a good foundation for it and its chimneys; but the distance which the heated blast would be required to travel before reaching the twiers, would be an objection.

Fig. 4.
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b

C d

The hot-oven is built and arched over with brick, and strongly bound externally with iron, the heat being sufficient to destroy supports passing through it. It is sufficiently large to contain a small forest of upright flattened pipes about ten feet high, with an internal cavity of about four by seven or eight inches, the thickness of the metal being about an inch. These are maintained at a red heat, the blast through them preventing their destruction. They stand upon two large pipes or cylinders about a foot in diameter, and from twelve to fifteen feet long, with a single row of apertures, (a, d, fig. 4,) and one or more (b, c) large enough to admit of a double row of apertures. Over the neck of each aperture, a detached collar is placed, into which a pipe is firmly cemented, and the heads of two pipes on adjoining cylinders are similarly connected by an auxiliary pipe forming a semicircular or gothic arch, as represented in section in the upper part of the figure. The blast entering the first cylinder at a, meets a partition near the middle, and has to pass through the seven openings and pipes across the arched heads into b, and so on to d d, when it passes in the opposite direction to its place of exit at g, whence it descends to the twiers. The partitions are not in the middle of the cylinders, because by the time the air has passed half through them, it requires more room on account of its expansion.

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The operations and general results of smelting iron with anthracite, may be given at a future period.

ART. VIII.-Notes on some Ferns of the United States; by Professor KUNZE of Leipzic, 1846.-(Communicated by Dr. G. ENGELMANN.)

THE plants of this family prefer the climate of ocean-islands, more particularly within the tropics; the number of species is very limited on the large continents, especially in cold or temperate latitudes. We observe the same fact in the United States; the ferns of which are not numerous, though it is supposed that in the western and southern parts of the union, several may yet be discovered. Several species new to the flora of the United

States have been communicated to me; their description, and some further notes on some North American ferns, are here offered to the botanists of the Union, who will oblige me exceedingly by communicating ferns, not known to me, and thereby assist my investigations on this family.

The most complete enumeration yet known to me is that of Nuttall's, (1818,) and the largest supplement has been furnished by Hooker (Flora Bor. Am., 1840). Many other data may be gleaned from numerous journals and other works, to collect and arrange which will be the task of some American botanist; I here offer merely some notes on the distinction of nearly related ferns, on some additional localities, and a few special remarks, in which I follow Nuttall's arrangement.

EQUISETUM. I have nothing to add to A. Braun's and Engelmann's memoir in this Journal, vol. xlvi.

LYCOPODIUM.-L. Selago, L., found in Greenland, on the mountains of New England (E. Tuckerman, Jr.), and on rocks at the falls of Broad River, North Carolina (Rugel!).-L. alopecuroides, L., on meadows between Quincy and Aspalaga, Florida (Rugel!). An elongated form densely covered with small leaves was collected on Lake Tamony, Florida, by Rugel!—A similar elongated variety is L. inundatum, L. 8. Bigelovii, Tuckerm.! (L. Carolinianum, Big., L. Bigelovii, Oakes and Tuck. !) from Plymouth, Mass. (Tuckerman!), and from Covington, Louisiana (Drummond!).-L. annotinum, L. 8. Spach Monogr. (L. pungens, Desv., L. annotinum, 8. montanum, Tuckerm.! L. sabinæfolium, Beck, non Mich. fide Tuckerm.) has been found, not only in Newfoundland and Labrador, but also on the White Mountains of New Hampshire (A. Gray! and Tuckerman!). -L. dendroideum, Mich. (L. obscurum, L.) has been found as far south as the Smoky Mountains of Tennessee (Rugel!).—L. Chamaecyparissus, A. Braun,* nearly related to L. complanatum, L., but probably well distinguished, grows also on the Chivi Mountains, Cherokee County, North Carolina (Rugel!).-L. lucidulum, Mich., one and a half feet high, New England, (Tuckerman!) of common size on the Black Mountains, North Carolina (Rugel!).-L. rupestre, L., is widely distributed in America and Africa, and from California to Mexico and Peru. Beyrich has collected it in the Southern States, and Rugel on the Broad river Mountains, North Carolina.-Nuttall's supposition, that L. albi

NOTE BY A. BRAUN.-L. Chamaecyparissus is preserved in Wildenow's herbarium from Canada, sent by Richard under the name of L. complanatum. L. complanatum of the North American authors belongs mostly to L. digitatum, (Dillen,) A. Braun; it is questionable whether the true Linnean L. complanatum, has been found in North America; a specimen collected in Kamtschatka by Ermann cannot be entirely identified, as it shows no fructification. L. sabinafolium is a very doubtful species of this section. To judge from a specimen in Willdenow's herbarium, I take it to be an alpine form of L. Chamæcyparissus.

SECOND SERIES, Vol. VI, No. 16, July, 1848.

11

dum might be only a variety of L. apus or apodum has lately been confirmed.

OPHIOGLOSSUM.-American specimens of O. vulgatum are not distinct from European ones.-A small species with an elliptical acute leaf as long as the spike, collected by Beyrich at Ebenezar, probably belongs to O. nudicaule (O. ellipticum, H. and Grev. A specimen of O. bulbosum, Mich., or more properly O. crotalophoroides, Walt., collected by Drummond in Louisiana and communicated by A. Gray, agrees exactly with O. tuberosum, Hook. from Talcahuano.-O. pusillum, Nutt., is entirely unknown in Europe and has not been mentioned by Greville and Hooker. Bot. Misc., iii.

BOTRYCHIUM.-The different species still require to be more accurately distinguished. B. gracile, Pursh, has been united with B. virginicum by Greville and Hooker. (1. c.) B. dissec tum, Muhl., is unknown to me.

OSMUNDA.-A. Gray has already proved the identity of O. Claytoniana, L., with O. interrupta. O. spectabilis, W., and O. regalis, L., cannot be separated any better. Nuttall has already pronounced them "scarcely distinct."

POLYPODIUM.-More correct observations are required regarding the species which resemble P. vulgare, L. P. vulgare, 8. americanum, Hook., (P. virginianum, L.,) differs from the European form by a narrower and more elongated frond, narrower lobes separated by wider sinus, the lowest being longer or at least not shorter than the following ones, and the sori being always nearer the margin than in the European plant. I have not met with any American specimens entirely agreeing with the true P. vulgare of the old world.-P. Scouleri, H. and Grev., Ic. Fil. 56, is incorrectly united with the very distinct P. Californicum, Kaulf., in Hook. Fl. Bor. Am. P. intermedium is unknown to me; it appears to approach P. Cambricum, Desv., the original form of P. Cambricum, L., and of the gardens, a common fern about the Mediterranean Sea, but may constitute a separate species.-P. incanum, L., appears to belong exclusively to the southern states, I have seen specimens from Louisiana (Flügel!), and from Louisiana and Florida (Rugel!).*-Polyp. connectile, (Mich.,) not distinguishable from P. Phegopteris, L., extends as far north as Newfoundland and Labrador.-P. Dryopteris, L., was sent to me from Labrador.-P. calcareum, Sm., widely differing from the last, is enumerated by Hooker; I have not seen any American specimens of it.

NOTHOCHLENA dealbata, Kunze, (Cheilanthes dealbata, Pursh, ii, 675, Nuttall, ii, 253, N. pulchella, Kze., in Mohl and Schlechtend., Bot. Zeitg., 1843, No. 37,) must be introduced here. This

* Grows as far north as on the Wabash in Indiana.—Engelm.

species is nearly related to N. nivea, though essentially distinct. I have only seen specimens obtained from the Berlin botanical garden, but Nuttall's and Pursh's diagnoses do not permit a doubt about the identity of the species. I would not have looked for it under Cheilanthes.*

WOODSIA. I cannot distinguish W. rufidula, Beck, (Nephrodium, Mich.,) from W. ilvensis, Br. The species varies, with ovate, acutish, elongated, obtuse or rounded fronds. Specimens from New York, sent by Prof. A. Gray, attain the height of six inches.-W. glabella, Br., Hook. Fl. Bor. Am. i, 237, is a very distinct species.

PHYSEMATIUM.-Ph. obtusum, Hook. Fl. B. Am. ii, 259. Hooker in Spec. Fil. i, 62, very properly unites Aspidium obtusum, W., and Woodsia Perriniana, Hook. and Grev., though under the name of Woodsia obtusa. This fern extends from the northeastern states to North Carolina, Missouri and Texas.

ASPIDIUM. I have so far seen no specimens of A. cicutarium, Spreng., from the United States.-Hooker refers A. Filix mas, Pursh, to A. Goldianum, H. and Grev., whether correctly or not, I cannot decide; but I have seen the true A. Filix mas from Newfoundland.-A. molle, Sw., appears to be unknown as an inhabitant of the United States; I have seen specimens from Louisiana, (Ludwig in Herb. Lucæ!), Alexandria, Louisiana, (Hale!) limestone rocks near Aspalaga, Florida (Rugel!), and banks of streams near Houston, Texas (Lindheimer in Herb. A. Braun!).-A. Thelipteris and A. Noveboracense, Sw., are declared by Hooker, Fl. Bor. Am., to be "quite identical." I cannot subscribe to this opinion. The latter species, Schk., t. 46, appears to me to be distinguished from the former by a shorter stipe, by the circumference of the frond being more narrowed upwards and downwards, by thinner texture, by narrower and ciliate segments of the pinnæ, and by entire veins (Presl therefore arranges both species in different sections of his genus Lastrea). I have seen A. Noveboracense from New York (Halsey), Pennsylvania, (Poppig), Arkansas (Beyrich), and North Carolina (Rugel).—I have seen no North American specimen of A. cristatum, Sw.-The identity of A. spinulosum, Sw., A. dilatatum, Sw., A. dumetorum, W., and A. intermedium, W., as different forms of one species, cannot be doubted any longer. A peculiar variety of A. spinulosum occurs in the northern latitudes and on the mountains of the Southern States, which must be studied more closely in its native localities, as it may prove to be a distinct species. I have specimens of this form from Newfoundland, (La Pylaie,) Greenland, and Labrador,

Nothochlæna sinuata, Kaulf. Enum. Fil. 135. Kunze, t. 65. (Acrostichum sinuntum, Sw. Syn. Fil. Gymnogramma sinuata, Presl.) so far only known as a Mexican and Peruvian species, has been found by M. Lindheimer on the Guadaloupe river in Texas.-.9. Braun.