Page:Encyclopædia Britannica, Ninth Edition, v. 17.djvu/77

Rh M U S M U S 65 his grandson Sa id made Muscat the capital, and cultivated the friendship and commerce of the English in Bombay and of the United States, to the great advantage of the city. Under Sa id s successor Thuaini family feuds and the intervention of the Wahha- bites impaired the prosperity of the state. Thuaini was murdered in 1867, but after some further troubles his son Tnrki was estab lished on the throne by the aid of British influence. MUSCATINE, a city of the United States, the county seat of Muscatine county, Iowa, is built on a rocky bluff on the west bank of the Mississippi, at the apex of what is known as the Great Bend. It carries on a large busi ness in lumber, milling, canning fruits and vegetables, &c. Settled in 1836, and incorporated as a city in 1853, it in creased its population from 5324 in 1860 to 8295 in 1880. MUSCINE^E. The Muscinese are a highly interesting class of plants on account of the important part they play in the economy of nature, and also from the remarkable conditions of their development and formation. In many parts of the world it is principally the mossy covering of forests which, by collecting the rainfall like a sponge, pre vents the pouring down from mountains of violent and excessive torrents of water, while the Bog-moss (Sphagnum) plays an important part in the formation of peat ; and many other Mosses which grow on rocks produce by the decay of their dead parts a thin layer of mould (humus) in which the seeds of higher plants are able to take root. The importance, however, of Mosses in a morphological point of view proceeds from their position in the botanical system. The Muscinese immediately follow the first divi sion of the vegetable kingdom, the Thallophytes, under which are included the Algae and Fungi, because their vegetative body is a &quot;thallus,&quot; that is to say, is not divided into stem and leaf like that of higher plants, nor are they possessed of roots like those observed in higher plants (Ferns, Conifers, Monocotyledons, Dicotyledons, &c.). Their anatomical structure is also very simple, the individual essential tissue-elements being but little differen tiated from each other. The Muscineae agree in many of their conditions with the Thallophytes, in others again with the next higher division, the vascular Cryptogams (Pteridophytes), to which the Ferns, Equisetums, and Lycopodiums belong. In many Muscineae of the division of Liverworts (Hepa- ticse) the vegetative body has still the form of a thallus (fig. 1), which is ribbon-shaped and grows in close con tact with the substratum. There are, however, several gradual stages of transition from this ribbon-shaped thallus to a leaved stem, such as many Liverworts (Hepatic*) and all Leaf-mosses (Mtisci frondosi} possess. Yet the struc ture of the leaves and of the stem, even in the latter, is very simple. The leaves present for the most part a cell- surface of one layer, and that (if we leave out of sight those in the middle part of the leaf, which in Leaf-mosses form the &quot;mid-rib&quot;) is ordinarily composed of cells of uniform character. There is thus no epidermis as in higher plants, and the leaf itself attains but very trifling dimensions. The stem is also of simple structure ; it possesses no &quot;vascular bundles,&quot; but consists only of simple cells, among which there is no differentiation, except that those which lie outside often have thicker walls, and thus form a firmer rind-layer, while the interior ones are more elongated and serve for the storage and transmission of the plastic substances (albumen, hydro carbons, &c.). The roots also by which the stems are attached to the ground are of very simple organization. They are either hair -like tubules as in many Liverworts, or rows of cells as in the Leaf -mosses. To distinguish them from the roots of higher plants they have been termed &quot; rhizoids.&quot; In many cases the vegetative body scarcely attains one twenty-fifth of an inch in length, in others, however, it rises into a much -branched form of from about 4 to about 1 2 inches or more. The duration of its life reaches in some small forms (Ephemerum, Pliascum, &amp;lt;fec.) only a few weeks or months ; in most cases, how ever, it is virtually unlimited, since the vegetative body continues to grow at its point while the older parts below are dying away. From this cause too the branches are isolated from each other, and become independent plants. In a peat-moor, for instance, the Bog-moss plants on the upper surface are the points and branches of the very same plants whose under-parts have long ago died away, and have principally contributed to the formation of the peat. This isolation of the branches through the dying away of the older parts which keep them together is at the same time a means of multiplication. Mosses also possess many other arrangements for asexual multiplica tion, as through gemma?, &quot; innovations,&quot; ttc. In the Liver worts, for instance, almost every cell is capable of giving origin to a new plant. The most extensive propagation, however, of the Mosses is that by means of spores, small roundish cells which are formed in a peculiar capsule, the sporogonium. The forma tion of these sporogonia is especially characteristic of the Muscineaa. They originate, as a consequence of fertiliza tion, from a cell the ovum-cell which is generated in the female sexual organ, the archegonium. These arche- gonia (fig. 6) have, when ready for fertilization, the form of a flask. They consist of an inferior and somewhat swollen portion, which contains the ovum-cell, and of a superior portion drawn out to some length, the neck. The neck forms a canal through which the male fertilizing bodies, the spermatozoids (fig. 5, D enter to blend with the ovum-cell. In the immature condition the arche gonium is closed, its neck portion is filled up with a string of cells and covered at the top by a layer of cells which closes it like a lid (fig. 6). At a later period, however, the membranes of the string of cells which fills up the neck (the canal-cells of the neck) are converted into a jelly, which on contact with water swells up greatly, forces open the apex of the neck portion, and thus pre sents an open access to the ovum -cell. The mucilage which arises from the swelling up of the canal-cells of the neck is also so far of importance with regard to fertiliza tion that by it the freely-moving male fertilizing bodies are stopped when they reach the neck of the archegonium. The male fertilizing bodies are here, as in many Algae, in the vascular Cryptogams, and in most animals, termed spermatozoids. They are spirally -coiled filaments, thick ened at the posterior extremity, finely pointed at the anterior, and bearing at this thin end two long fine cilia by means of which they can move in water. The sperma tozoids are formed in the male sexual organs, the an- theridia (fig. 5, (7), which are bodies with long or short stalks, and of spherical, oval, or club-shaped form, sur rounded by a wall -stratum consisting of a simple layer of cells, and which possess in their interior a tissue formed of numerous small cells, in each of which one spermatozoid takes its origin. When the wall-layer of the antheridium is torn asunder the spermatozoids are set free at its apex, and move in water by means of their cilia, like Infusoria. Thus water is always necessary to fertilization ; it is only in water that the neck of the archegonium opens, and that the spermatozoids can move. Since either the Mosses grow in moist localities, or those which spring up in dry situa tions always form little turfs so as to suck up every drop of rain like a sponge, their fertilization is always secured, provided the organs of both sexes are present. Even before the opening of the archegonium-case the oosphere has formed itself in the inferior portion of the archegonium. Originally in this inferior ventricose por tion of the archegonium is a large cell, the central cell XVII. 9