ALLIANCE IV.-MUSCALES-THE MUSCAL ALLIANCE.

CELLULARES FOLIACEE, DC. Theor. Elem. 249. (1819).-PSEUDOCOTYLEDONEE, Class I. Agardh, Aph. 103. (1822).-HETERONEMEA, Fries Syst. Orb. Veg. 33. (1825) in part.-AcoTYLEDONES, Class 2. Ad. Brongniart in Dict. Class. 5. 159. (1824).-CRYPTOGAMICA, 2d Circle, T. F. L. Nees v. Esenbeck and Ebermaier Handb. der Med. Bot. 1. 18. (1830).-HEPATICE and MUSCI, Endlicher Gen. 42. and 46.

DIAGNOSIS.-Cellular or vascular Acrogens, with the spore-cases either plunged in the substance of the frond, or enclosed in a cap-like hood.

NEXT after the Algal series follows that which derives its name from Mosses, presenting at one point a structure nearly as simple as that of Lichens, and at another a complexity of organization unknown elsewhere among Acrogens. The Crystalworts (Ricciaces), by which the series begins, are mere lobes of green or purple parenchyma floating in water or spreading over mud, and multiplied by reproductive particles (spores) generated in hollow flask-like cases. Then follow masses of species gathered together under the names of Liverworts (Marchantiaceae) and Scalemosses (Jungermanniaceae), whose stems and leaves are, in the majority of instances distinctly separate, and among whose spores are formed elastic threads with a powerful hygrometric quality and of unknown use. Finally the ranks are closed by Splitmosses (Andræacea), and Urn-Mosses (Bryaceae), which have in all cases a distinct axis of growth, symmetrical leaves, and a complicated reproductive apparatus formed by the adhesion of leaves in rings or whorls: in emulation, as it were, of flowers, in the more completely organized classes of Endogens and Exogens.

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In the opinion of a large number of modern observers there are two sexes in all these plants, the one bearing the name of Antheridia (or false anthers), and the other of Pistillidia (or false pistils). That such organs exist is certain; the question is whether or not they are to be looked upon as connected with sexual qualities. Those who regard them in that light have naturally taken the imbedded oblong antheridia of Marchantia, and the stalked reticulated ones of Jungermannia, for anthers; but Hooker, in his beautiful Monograph of the latter genus, and also in his British Flora, (p. 459,) is unsatisfied as to their nature. Greville, in the Flora Edinensis, is in a similar state of uncertainty; and Agardh admits nothing more in them than a resemblance to male organs, adopting the opinion that they are a particular form of gemmules. Mirbel considers the cups or baskets of Marchantia to be filled with little buds, and the peltate receptacles to be male flowers, while the stalked recep

Fig. XXXIV.

tacles are masses of pistils. (See his admirable Memoir, tt. vi. et vii.) On the other hand Greville and Arnott, in the fourth volume of the Transactions of the Wernerian Society, speak thus positively against the sexuality of the organs in question :

"What the organs really are, in the plants under review, which the accurate Hedwig so well figured and described under the name of stamens, we leave to others to decide; but we cannot help entering our protest against those bodies called Stamina and Pistilla (the young theca) being regarded in a similar light with the same organs in more perfect plants. Though,' says Sprengel, I have formerly been a zealous advocate for Hedwig's Theory of the Fructification of Mosses, it has nevertheless appeared to me an insurmountable objection, that the supposed anther can again produce buds and strike roots; which is certainly the case with regard to the disks of Polytrichum commune,

Fig XXXIV.--1. Young spore-cases and paraphyses of Mnium cuspidatum. 2. Antheridia and paraphyses of Polytrichum commune. - 'Link.

Bartramia fontana, Bryum palustre, undulatum, cuspidatum, punctatum, and with those of Tortula ruralis. In Bryum argenteum we see the buds containing the supposed anthers constantly drop off, strike root, and produce new plants; this I have observed myself times out of number. Still more in point is the experiment first made by David Mees, of sowing the stellule of Polytrichum commune, containing merely club-shaped bodies, when he found that plants came up, which in their turn produced fruit. Another excellent naturalist, Dr. Roth, has made similar observations with regard to Hypnum squarrosum and Bryum argenteum. It is more probable, therefore, that these supposed anthers are mere gemmæ, produced by the superabundance of the juices, and hence surrounded by succulent filaments."" Fries also, in his Planta homonémeæ, xxxi., expresses himself thus, "Musci sunt esexuales et in dicta organa masculina meras esse gemmas vix dubium videatur.”

Nevertheless, in the face of this evidence, Adolphe Brongniart retains a belief in the sexuality of Mosses, and in the male functions of the axillary bodies; and he says, with justice, that it appears from Brown's mode of describing Mosses, that he entertains a similar opinion. Dr. Taylor also thinks that the Liverworts show the presence of two sexes in the most evident manner. (Linn. Trans. xvii. 375.) That the flask-like bodies called pistillidia are female organs he considers proved by the germination of the dark brown particles (spores) that are contained within them. He admits that no direct evidence exists to show that the antheridia are male organs; but he says that they discharge a viscid whitish liquor, which is rapidly dissolved in the air, uniformly precede the pistillidia, and have fulfilled their office before the seeds (spores) are ripe. Dr. Montagne follows on the same side (Ann. Sc. Nat. 2 Ser. ix. 100), with the sweeping assertion that "no body now-a-days (1838) doubts that Mosses and Liverworts have two sexes." Mr. Valentine, in two elaborate papers (Linn. Trans. xvii. 465, and xviii. 499), denies the sexuality of some plants at least of the Muscal Alliance; justly observing, however, that the experiments mentioned by Sprengel and Mees are unsatisfactory, there being no proof in them that it was the antheridia which grew; it might have been the whole mass of the stellate disks in which the antheridia occur. Valentine relies upon the very important fact, first remarked by himself, that the pistillidum, in which the spores are produced, is not in existence at the time when the antheridia are in action. Like Mohl and Agardh, he maintains that the spores, although equivalent to seeds, are almost identical with pollen grains. "The only difference," he adds, "that I can find between pollen and sporules is, that the coat of the latter is of a more rigid and opaque texture. From this difference it is that the sporules rarely burst in a sudden manner upon the application of water; but when they do, the moving particles are discharged loose in the water, precisely in the same manner as are those of pollen."

Mr.

Upon this point however Mr. Griffith observes, that "it is to be borne in mind, that whereas pollen is the result of a simple separation constituting a primary and independent process; in Musci, Hepatica, Salvinidæ, the spores, otherwise so similar to pollen, are the result of a secondary process, dependent on a primary one which appears to be remarkably analogous to phanerogamic fecundation."

Finally, Unger in his account of the anatomy of Riccia (Linnæa, xiii. 13), states that antheridia and pistillidia are alike at first, that the contents of the first are lost, of the second retained, and that the first perishes while the second is permanent, whence it is reasonable to presume that the emission from the antheridia is a necessary condition for the formation of spores. He therefore regards them as male and female.

It seems clear from all these statements, that the question of sexes in the Muscal Alliance is undecided. There is no doubt that two very different sorts of organs exist among its species; but it does not appear to me that we have sufficient evidence at present to show that the antheridia are male organs. So far as they are concerned we have conjecture and nothing more. All that is proved is: 1. That the spores are bodies which reproduce the plant, and are, therefore, analogous to seeds; and 2. That the structure of the antheridia and pistillidia is wholly at variance with that of anthers and pistils properly so called.

Mr. Griffith, nevertheless, in an elaborate Memoir on Azolla and Salvinia, published in the Calcutta Journal of Natural History, adopts in the fullest extent the opinion that Acrogens have sexes, as will appear hereafter. It is, however, to be remarked that the question is not, whether there may not be in such plants as these some trace of a male and female principle, or certain organs in which it is probable that such a principle resides; but whether there is any such structure as that which we know to be sexual in all the classes of plants higher than Acrogens. And I must confess, after reading Mr. Griffith's very learned and ingenious observations, that my opinion remains unshaken as to the existence of most essential differences between Acrogens and other plants in all that regards the organs of reproduction.

A remarkable point of structure in Liverworts is the spiral filament, or elater, as it is called, lying among the sporules within the spore-case. This consists of a single fibre, or of two, twisted spirally in different directions, so as to cross each other, and contained within a very delicate, transparent, perishable tube. They have a strong elastic force, and have been supposed to be destined to aid in the dispersion of the sporules, a most inadequate end for so curious and unusual an apparatus. It is more probable that they are destined to fulfil, in the economy of these plants, some function of which we have no knowledge.

One of the most extraordinary points in the history of the Muscal Alliance, is the fact that in the cells of the antheridia are generated bodies having what seems to be spontaneous motion, and apparently of the same nature as the speriaatic animalcules of animals. This unexpected fact has been fully and correctly described by Meyen, (Ann. Sc. Nat. N. S. x. 319), who has found the same creatures (?) in the correspond

Fig. XXXV.

ing organs of Chara and Marchantia. Unger has also published an elaborate Memoir upon this singular subject. (Ann. Sc. N. S. xi. 257 and 274.) He describes the spiral threads of Sphagnum thus :-"These animalcules consist of a thick and swollen body having a slender threadlike appendage. The length varies between the 0.0025 and 0.0020 or 6 to

of a line Vienna measure. The length of the appendage is about 44 longer than the body, so that the total length of the animal may be stated to be the 0.01 of a line." It is to be observed by those who may search for such bodies that they can only be found just when the antheridium is completely formed, and that a magnifying power of at least 600 diameters is required for their detection. Unger regards them as analogous to the genus of animalcules called Spirillum. It is so improbable that animals should be generated in the cells of plants, unless accidentally, that we cannot but entertain grave doubts whether, notwithstanding their locomotive powers, these bodies are really any thing more than a form of vegetable matter; and it is worth considering if they may not after all be a diminutive representation of the clavate processes surrounding the spore of Equisetum, and perhaps of the claters found in the spore-cases of Liverworts. This is certain, that the spores and elaters of Equisetum, when at rest, have very much the appearance of the Spirilla in the antheridium of an Urn Moss or a Chara; and since it has been proved that the spiral filaments of Equisetum arise from the splitting of a cell in which a spore is generated, there seems no reason why a similar action should not take place in cells that are destitute of spores. As to the motion, how are we to tell that it is not a hygrometrical action? There is as active a motion in the elaters of Equisetum as in the spirilla of Mosses, only it arises in the former from drying and in the latter from floating in water. Nägeli has lately found the spiral threads of Liverworts in the leaves of Ferns.

Equisetum may be regarded as a link between this alliance and Chara on the one hand, while its high degree of composition brings it into the neighbourhood of Ferns and Clubmosses.

By some Botanists the orders of the Muscal Alliance are separated into two great groups, Hepaticæ and Musci; of which the former are without an operculum and have for the most part elaters, while the latter have an operculum and always want elaters. But such distinctions seem to be of hardly sufficient importance to be employed for higher purposes than the distinction of Natural orders.

1. HEPATICE.

NATURAL ORDERS OF MUSCALS.

Spore-cases valveless, without operculum or elaters

15. RICCIACEÆ..

Spore-cases valveless or bursting irregularly, without 16. MARCHANTIACEÆ.

operculum, but with elaters

Spore-cases opening by a definite number of equal valves,}17. JUNGERMANNIACEA

without operculum, but with elaters

Spore-cases peltate, splitting on one side, without oper-
culum, and with an elater to every spore

2 Musci.

Spore-cases opening by valves, with an operculum, with-}

18. EQUISETACEE.

19. ANDREACE

Spore-cases valveless, with an operculum, without elaters. 20. Bryacea.

ORDER XV. RICCIACEAE.-CRYSTALWORTS.

RICCIEE, Nees Leberm. 86; Bischoff in Nov. Act. xvii. 2. 964; Lindenb. ibid. xviii. 412.-RICCIACEAE, Endl. Gen. xvii.

DIAGNOSIS.-Spore-cases valveless, without operculum or elaters.

Terrestrial herbs, of diminutive size, inhabiting mud or water, swimming or floating, usually annual, their leaves and stems blended into a frond of a cellular structure,

Fig. XXXVI.

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creeping, green or purple underneath, with a distinct epidermis, and a cavity of air-passages beneath it in some species. Antheridia immersed in the frond, with their mouth projecting in the form of a papilla, or a slender cone. Pistillidia in the frond of the same or a different individual, immersed or superficial, sessile or stalked ; the common involucre either missing or scaly; the involucels none,

or in the form of little bladders perforated at the point. Sporecases membranous, united to a calyptra, or distinct from it, globose, bursting irregularly when ripe. Spores triangular, pyramidal, and half round, without elaters.-Endl.

These little plants form a plain transition from Thailogens to Acrogens. They have that combination of leaves and stem into what is called a frond, which is characteristic

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of Lichens, and their spores may be not unaptly compared to the tetraspores of the Rose-tangle order. But, on the other hand, their spores are collected in large numbers within organs resembling the pistils of phænogamous plants; they have a distinct axis of growth, and an epidermis is distinctly formed with stomates for breathing with. (See Lindenberg, 1. c.) While, however, for the latter reasons, they are to be regarded as more elevated in the scale of organization than Lichens, or similar plants, they are inferior to Liverworts and Scalemosses, because of the absence of those spiral springs called elaters, by which, in the latter orders, the spores are dispersed; and to Split-mosses and Urn-mosses, because they want the complicated apparatus which is added to the spore-cases of those orders, under the form of either an operculum, or peristome. According to Endlicher, the Crystalworts pass through Corsinia into the tribe of Liverworts, and by Sphærocarpus into that of Scalemosses. There is a detailed account, by Unger, of the anatomy of Riccia glauca, in the Linnæa, vol. xiii. p. 1. The genus Durica is regarded by Messrs. Bory and Montague as forming the nearest transition to Liverworts; they describe it as fructifying under water, which is very seldom the case with the other Crystalworts. Ann. Sc. N. 3 ser. i. 225.

Fig. XXXVII.

Of the species hitherto known, two-thirds have been observed in Europe, and the remainder in various parts of the world. Several species in North America, the Cape of Good Hope, and Brazil, appear to be very similar to those of Europe.-Endl. The uses of Crystalworts are unknown.

Fig. XXXVI.-J. Riccia ratans, a lobe magnified; 2. a portion of it, showing the spore-cases cut open; 3. spores.

Fig. XXXVII.-Riccia glauca. 1. A young spore-case; 2. an antheridium; 3. spores as they lie in the mother cell. (Unger.

ORDER XVI. MARCHANTIACEAE.-LIVERWORTS.

Hepaticæ, Juss. Gen. 7. (1789); DC. Fl. Fr. 2. 415. (1815); Agardh Aph. 104. (1822); Nees ab Esenb. in Martius, Fl. Bras. 1. 295. (1833); Hooker's British Flora, vol. ii. p. 97. (1833); Bischoff de Hepaticis in Act. Acad. Nat. Cur. xvii. pars 2. (1836); Ann. des Sc. 2. ser. 4. 309. (1836).— Marchantiaceæ and Targioniaceae, Ed. pr. Endl. Gen. xx. — Marchantieæ and Targionieæ, Nees Lebermoose, 84.- Marchantieæ, Taylor in Linn. Trans. 17. 377.

DIAGNOSIS.-Spore-cases valveless, or bursting irregularly, without operculum, but with elaters. Plants growing on the earth or trees in damp places, composed entirely of cellular tissue, emitting roots from their, under-side, and consisting of an axis or stem which

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is leafless, but bordered by membranous expansions, which sometimes unite at their margins, so as to form a broad lobed frond, having a distinct epidermis pierced by stomates. Antheridia either immersed in the frond, or placed on disk-like sessile or stalked peltate receptacles. Pistillidia lurking within involucres, either placed below the edge of the frond, or on the edge or under-side of stalked heads. Spore-cases stalked, opening by irregular fissures, or by separate teeth. Spores globose, with elaters.

With these plants organization advances another step. To the spores of the Crystalworts are added spiral threads or elaters for their dispersion; and various lacerated membranes surrounding the spore-cases seem to be imitating the calyx and 3 corolla of perfect plants. There is still, however, a want of true leaves, which are fused, with the stem, into a frond. The principal part of the order has the sporecases raised on a long stalk, and clustered into a head; but this character is missing in Targioneæ, which Endlicher regards as a distinct order. In these plants, as in Mosses and Charas, each cell of what are called the antheridia contains a body resembling an animalcule of the genus Vibrio, which moves about rapidly in water, as soon as it is liberated from its birth-place. Germination takes place by an universal increase and enlargement of the spore, which becomes lobed, as it were, by the swelling of the cellules, and is afterwards nourished by the emission of a radicular fibre. The original development of Ferns and Liverworts is much the same. Fl. Bras. i. 299.

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Fig. XXXVIII.

The Liverworts differ from Crystalworts in having elaters and involucrate spore-cases, and from Scalemosses or Jungermanniaceae, in the want of power to separate their sporecases into distinct valves.

Natives of damp shady places in all climates; two were found in Melville Island. The only atmospheric condition to which they cannot submit is excessive dryness.

Little is known of their uses. De Candolle thinks it probable that the larger kinds will be found to resemble foliaceous Lichens in their qualities. A few are slightly fragrant, with a subacrid taste. They have been employed in liver complaints, but their use seems a mere superstition. It is, however, alleged that Marchantia hemisphærica has really proved advantageous in dropsical affections.

Equisetacea.

POSITION. Ricciaceae.-MARCHANTIACEA.-Jungermanniacea.

Lichenaceæ.

Fig. XXXVIII-1. Marchantia commutata, natural size; 2. a head of spore-cases; 3. a section of the disk which bears the spore-cases; 4. elater; 5. granular spore.