14 FIBRES. EPIDERMIS. 



b) are cavities which are sometimes in the form of short blunt 

 tubes, and sometimes they are elongated very much ; they en- 

 close the particular juices of the various species of plants. 



22. Finally, the vessels of the latex are ramified canals, 

 which may be considered as a sort of proper vessels ; according 

 to some botanists, they are lined by a proper membrane, but ac- 

 cording to other observers, they have no lateral parietes, and are 

 merely inter-cellular passages or meatus. (Latex is a Latin 

 word, signifying a peculiar fluid, which is usually turbid, and 

 coloured red, white or yellow; often, however, colourless.) 



Of the Compound Constituent Parts of Organs. 



23. The elementary parts of plants we have just mentioned 

 constitute, either alone or by their union, the tissues and the dif- 

 ferent organs which, in their turn, concur in the formation of the 

 various apparatuses constituting the body of these beings. Such 

 are the fibres, the epidermis, the hairs, the glands, &c. 



24. Fibres. The fibres which are often found in the different 

 parts of plants, but chiefly in the stems, are not composed of a 

 peculiar tissue, but are formed of vessels united in bundles, inter- 

 mingled with clostres or elongated cells. Among these vessels, 

 we sometimes find tra'chese, but most of them are punctuated 

 vessels. The filaments thus formed are arranged parallel to each 

 other, and joined together by a more or less loose cellular tissue ; 

 it is therefore much easier td separate them lengthwise than 

 transversely. 



25. Epidermis (from the Greek epi, upon, and derma, skin). 

 The epidermis or cuticle fl .... 



is a thin membrane which 



covers the external surface 



of plants; it is especially 



distinct in the young 



stems, the leaves and 



roots ; it is composed of ' '' ' 



cellular tissue, the cells of 



which adhere more strong- ** 9.-vERT,cAL SECTION OF A LEAF. 



ly to each other than to the subjacent parts, and for this reason 



Explanation of Fig. 9. Vertical section of a leaf magnified ; a. the 

 epidermis of the upper surface ; 6. the paren'chyma formed of cellular 

 tissue, in which we observe inter-cellular passages or mea'tus ; c, c. epi 

 dermis of the lower surface ; rf, d, d. the stoniata cut transversely. 



22. What are the latex vessels ? 



23. What elementary parts constitute the tissue of plants ? 



24. What aro fibres ? 



'J What is meant by epidermis ? What are sto'mata ? Whore are 

 they found ? 



