others; concerning the organs of which there has been much controversy, as is very ably and satisfactorily stated by Dr. S. in the seventeenth letter.

In searching for the parts of fructification in mosses, there will be found, as was first ascertained by Micheli, two distinct sets of organs; the one consisting of small clubshaped or capitated bodies generally inclosed by themselves, but sometimes with the second set of organs, in a little bud or stellated expansion of the leaves; at a certain period of their growth the tops of these club-shaped bodies are entirely resolved into a minute granular powder, after which they decay and disappear. These bodies were supposed by Micheli, and after him by Hedwig, to be the anthers or male organs of the plant; and indeed their form, the bursting of their summits, and their subsequent decay, appeared extremely analogous to the evolution and progress of the same parts in the phænogamous plants. In further confirmation of this it may be remarked, that those plants on which none but these anther-bearing buds are discoverable are always barren, that is, they produce no capsules. To this theory the only valid objection is, that in some species these buds fall off naturally or have been artificially detached, and after being thus separated have been observed to strike root in the moist ground, and become in due time perfect plants. Hence it is argued, that these buds are proper gemmæ, like those of the proliferous sedum, and therefore that the supposed anthers are organs, the use of which is unknown. This however does not appear to be a just conclusion, for it may well happen in such simple and vivacious plants as the mosses, that the leafy perichætium after it has answered its immediate purpose of protecting the anthers,

should fall off, take root, and assume an independent existence.— The male blossoms of Vallisneria are well known to detach themselves. spontaneously from the parent plant, and (which in our opinion. greatly adds to the probability of this double office of the perichætium,) there have been in many instances discovered among the supposed anthers, jointed filaments exactly similar in appearance to the rudiments of roots in other parts of the plant, and for which no use has hitherto been assigned. The second set of organs is, like the former, inclosed in leafy receptacles. Their form is that of an oblong body, out of which proceeds a kind of tubular stem, either terminated by a simple blunt extremity, or bifid. In one or two species these bodies are solitary, but in general a considerable number are inclosed in the same receptacle, of which however it rarely happens that more than one arrives at maturity. In process of time this oblong body becomes enlarged, the terminating tube becomes impervious, the external membrane is gradually inflated and disengaged, except at its upper extremity, the peduncle which was at first scarcely visible is rapidly elongated, and when the change is complete the whole presents the appearance of an unilocular capsule, (containing small round bodies) covered with a calyptra, and elevated on a long simple stalk. The whole of this apparatus was considered by Linnæus as an anther, but more accurate observations have shewn, that the small round bodies contained in the capsule are actual seeds, the germination of which has been very satisfactorily demonstrated by Hedwig, and others. Hence it follows, that the oblong bodies are to be considered as germens, and their perforated stem as a pistil.

Those who are familiar with the investigations of Hedwig on the

germination of the seeds of the mosses, have, we doubt not, been struck, and at the same time puzzled, with his representation of their cotyledons, at first simple, and afterwards becoming branched in proportion to the growth of the young plant. This eminent observer has indeed only described what he actually saw, but the acuteness of our author, corroborated by his own experience, has solved the anomaly very satisfactorily, by shewing that the supposed cotyledons are only the rudiments of a common conferva which generally infests garden-pots in Germany, appearing on the surface of the mould at the same time as the mosses, and not overgrown by these latter till they have nearly arrived at their full

size.

Having thus explained the physiology of the mosses, Dr. S. proceeds to justify the determination of the genera of this class of plants, rather from characters taken from the capsule, than from the parts of fructification themselves. After this, in the twentieth and twenty-first letters, he describes at large every genus, and concludes with the following synoptical exhibition of the several characters.

"I. Capsule without lid and without
regularly shaped mouth Phascum.
"II. Capsule with a lid divided into
Schistostega.
"III. Capsule with naked mouth
A. calyptra bursting transversally

rays

Sphagnum.

B. calyptra deciduous, and of the

usual form

Gymnostomum. "IV. Mouth of the capsule furnished A. with a simple peristome

1. with teeth proceeding from the
outer, or from both the inner and
outer surface of the capsule
a. with four distinct teeth

a a. the common cortical substance wholly surrounding the external surface of the reservoir of the seeds,

Spherophoron.

8. in round reservoirs on proper peduncles; bb. the common cortical substance forming the nucleus of the reservoir, which is surrounded by the seminal layer, 9. in margin-less pilidia on proper pedicles : Baomyces. 10. in heads, marginated at first, sessile on the frond;

processes

Stereocaulon. cc. the common cortical substance forming the external margin of the concave scutellæ, which have also a proper margin; (11.) Urceolaria. . seeds round and cohering as if concatenated; the cortical substance surrounding only the lower surface of the reservoirs, and forming radiated around the latter, 12. in flat orbilla, with filiform frond; Usnea 13. in disciform orbillæ, with stiff, shrub-like frond; Cornicularia. c. Seeds lodged in proper pellucid membranaceous purses. The cortical substance forming the whole many-celled thalamium; (14.) Thelotrema d. Seeds fodged in proper delicate tubes of the seminal layer.

a a. the common cortical substance forming the margin of the

"This table, which accords with the present state of our knowledge, will probably admit of many alterations when the structure and propagation of the related plants, especially the Confervæ and Fungi, shall have been submitted to a careful examination."

We have thus presented the reader with a general view of the valuable matter contained in the volume before us; which we recommend to the careful perusal and study of all those who are desirous of cultivating this interesting but difficult branch of Natural History. We ought not to omit mentioning in further commendation of the work, that it contains ten coloured plates representing very faithfully and elegantly the essential characters of all the genera described, with the exception of a few of the musci hepatici.

IT will readily be allowed that the modern naturalist is under no necessity of applying for informa

tion to those writers of antiquity who have directly or incidentally treated of this interesting branch

of human knowledge. Yet as the languages and literary remains of the Jews, the Greeks and the Romans, have long and deservedly held a high place in the estimation of modern Europe, it is desirable that we should acquire all the information concerning them that is to be had. For this purpose several illustrious naturalists, chiefly of the Linnæan school, have visited Palæstine and the neighbouring regions, the results of whose inves tigations have in various instances been happily applied by biblical critics. Nor are the writings of the ancient Greeks capable of receiving less illustration by a careful enquiry into the natural history of those regions, both in Europe and Asia, which were formerly inhabited by that renowned people. It is therefore with peculiar satisfaction that we welcome the appearance of a Flora Græca, as calculated to be alike serviceable to the science of botany and literary criticism.

The materials for this work were collected by J. Sibthorp, M. D. Regius professor of botany in the university of Oxford. One of the travelling fellowships, founded by Dr. Radcliff, having been con ferred on our professor, he set out on his travels in the year 1785, accompanied by Ferdinand Bauer, one of the most able and accurate botanical draftsmen in Europe. After a laborious journey through Germany, Italy, and Sicily, he directed his course to the continent and islands of Greece, intending there to collect all the information that should fall in his way relative to the natural history, agriculture, and medicine of a country formerly the most illustrious in the world for freedom and science, but now groaning under the ignorant despotism of the Turks. In these pursuits he occupied himself for nearly two years, and in 1787, returned home with a large and valuable ANN. REV. VOL. VII.

treasure of drawings and dried plants.

From these materials and his own manuscript observations Dr. Sib. thorp immediately set about the composition of a Flora Græca, diligently comparing the specimens collected by himself with those of the Sherrardian, Banksian, et Linnæan herbariums. In the course of this investigation he found that his own acquisitions, ample as they were, did by no means correspond to the magnitude of the plan which he had in view; he therefore undertook a second journey to Greece, from which he returned in 1795, exhausted by fatigue, in consequence of which he shortly after died. Foreseeing this event however, and apprehensive lest the fruit of so much labour might be lost to the public, he employed himself, almost to the last day of his life, in the arrangement of his drawings and specimens. Out of those which had been collected in h's first journey he made choice of a thousand plants (not figured either in Curtis's Flora Londinensis, or in any of the works of Jacquin that had appeared previous to Dr. Sibthorp's second journey) and directed in his will that they should be published in ten volumes folio, accompanied by a Prodomus in octavo, without figures. In order to defray the extraordinary expences of so magnificent a work, he conveyed to the university of Oxford a landed estate of the annual value of about 3001, directing that the income should first of all be appropriated to the publication of the Flora Græca, and afterwards be applied to found a professorship of agriculture and rural economy in the above mentioned university. He further requested of his execu tors, J. Hawkins, and T. Platt, esqrs. to seek out for some learned botanist to whom should be entrusted the office of editing the proposed work, and especially of drawing up,

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