THE POPULAR EDUCATOR. 



LESSONS IN BOTANY. XXXIX. 



SECTION CXX. CRYPTOGAMIC PLANTS. 

 THESE we have already glanced at in a former part of our 

 lessons. Their organisation is very curious and exceedingly 

 diverse ; but in consequence of the absence of flowers, or at 

 any rate recognisable flowers, their study is not so easy as that 

 of the flowering plants. The most remarkable tribes belonging 

 to this division of plants are the mosses, lichens, fungi, ferns, 

 and sea-weeds, and to these we shall now direct the reader's 

 attention. 



SECTION CXXL MOSSES. 



There is no season of the year in which we may not find 

 interest and employment 

 amid the mosses and 

 lichens no soil nor 

 situation where some or 

 other of one or both fami- 

 lies may not be found. 

 Scarcely any part of the 

 world is destitute of them. 

 On the coasts of the Icy 

 Sea, where the soil never 

 thaws for more than the 

 depth of a few inches, 

 plants of these kinds are 

 said by travellers to be 

 the chief forms of vege- 

 tation. In Spitzbergen, 

 Greenland, and even in 

 higher latitudes, they 

 are abundant, as well as 

 on the morasses and vol- 

 canic tracks of Iceland ; 

 and on the frozen deserts 

 of Siberia, these little 

 cryptogamous plants may 

 still be found. Nor 

 only there ; for in the 

 arid wastes of burning 

 Africa, it is told us that 

 the traveller Mungo Park 

 was revived and rejoiced 

 by the sight of one of 

 the species of this lovely 

 tribe. 



The muscology of Bri- 

 tain,which contains about 

 four hundred species, 

 most nearly resembles 

 that of North America, 

 and is also closely allied 

 to that of the northern 

 and central parts of the 

 continent of Europe. It 

 is within less than a cen- 

 tury that this interesting 

 and widely extended 

 class of plants has been 

 made the subject of 

 much study or research. 



The Germans seem to have taken the lead in this branch of 

 botany, but they have been vigorously followed by many illus- 

 trious students of Nature among our own countrymen, and 

 new discoveries are daily being made in this department of the 

 vegetable kingdom. 



The structure of mosses is of the simplest kind ; fungi, sea- 

 weeds, and lichens alone being below them in the scale of 

 vegetation. With mosses commence the separation of root, 

 stem, and leaves, with which parts every jjlant of this tribe is 

 furnished, and in the place of a flower they have little vessels 

 usually supported on a stalk, and containing the seed. The 

 stems vary from the twelfth part of an inch to a foot in height ; 

 few of them, however, exceed four inches, and most are much 

 less. The leaves differ in form, some being egg-shaped, others 

 lance-shaped, and very many linear. If examined under a 

 microscope, these will often be found beautifully veined and 

 reticulated ; they have generally a bright-green hue, which 



280 



278. WALL SCREW MOSS (fORTULA MUKALIS) 1, CLUSTER OF SEED-VESSELS ; 2, 

 THECA OR FRUIT ; 3, PERISTOME ; 4, CALYPTRA. 279. CURVED FRUIT-STALKS 

 OF A MOSS. 280. ERECT FRUIT-STALKS Ot A MOSS. 281. FEUIT-STALKS OF 

 THE HAIR-MOSS (POLTTRICHUM). 



proves the activity of their breaihing apparatus ; yet thero are 

 species brown, purple, and even nearly black, as well as of the 

 palest whitish-green. The edges of the leaves are often toothed, 

 or notched like a saw. Mosses are said to be in fruit when 

 the little seed-vessel of which we have spoken is formed. 



The fructification of this tribe of plants is very peculiar, and 

 by it, more frequently than by any other part, is the species de- 

 termined. At certain seasons of the year we may observe a 

 forest of thin stems, crowned with these little seed-vessels, 

 rising above the general level of the clump of moss on which 

 they grow ; these stalks are called setae, or fruit-stalks, and the 

 vessels capsules. Let us take that species of moss which grows 

 so commonly on almost every wall we see, the Tortula muralis, 



or wall screw-moss (Fig. 

 278-1), as our example, 

 and examine it carefully. 

 The fheca (Fig. 278-2), 

 or fruit of this, has a 

 little cap, like that of a 

 Norman peasant, with a 

 high peak and long lap- 

 pet (Fig. 278-4) ; this is 

 the calyptra, or veil, and 

 forms a sort of hood, 

 which, when the fruit is 

 young, is rolled round 

 the theca, so as com- 

 pletely to cover it. As 

 the fruit-stalks lengthen, 

 this veil is torn from its 

 support and carried up 

 on the top of the seed- 

 vessel, much as the calyx 

 of the Eschscholtzia is 

 borne up on the summit 

 of the petals before the 

 flower opens. Now if 

 we place this seed-vessel 

 under the microscope, we 

 shall find that beneath 

 the veil is a lid or cover- 

 ing, which closes the 

 mouth of the capsule; 

 this, when the spores or 

 seeds are ripe and fit to 

 be dispersed, is thrown 

 off, and then new and 

 wonderful objects are dis- 

 closed ; underneath this 

 lid (which is called the 

 operculum) lies a kind of 

 tuft of twisted hairs (Fig. 

 278-3), which arise from 

 within the rim of the 

 theca, and are called the 

 teeth of the fringe, or 

 peristome. These do not 

 exist in all species of 

 moss, and when they are 

 found, differ in number; 

 but it ia an unvarying 



rule, that wherever they are seen at ail, their number consists 

 of four, or of some multiple of four, amounting occasionally to 

 as many as sixty-four. Sometimes the fringe consists of two 

 rows of teeth, differing in size, number, or arrangement ; and 

 this fringe acts in the most beautiful hygrometrical manner. 

 A theca of this same Tortula will illustrate our meaning, and 

 show this to be one of those beautiful and delicate arrangements 

 which the wisdom and goodness of God provides for the pro- 

 tection of the young seed. Take a capsule which has been dried 

 when the teeth were closed, and place it in water, or in a damp 

 place, and you will see its teeth unclose with a graceful and 

 steady motion which is beautiful to behold ; or if you breatlio 

 on a capsule when its fringe is expanded in the sunshine, the 

 slight moisture of your breath will make the little teeth in- 

 stantly close over the mouth of the vessel wherein the seeds 

 lie. In dry and sunny weather these teeth open, and the seeds, 

 when ripe, are scattered by the wind, and wafted to situations 



