THE ENDOGEXJE. 



147 



10. EQTJISETACEJE (Horsetails). 



The EquisetaceaB are the high- 

 est of the Acrogens, and 

 nearly resemble the Endo- 

 gens; they grow in ditches 

 and pools, have a hollow stem 

 with joints at regular intervals 

 from each of which a whorl of 

 green modified leaves arises ; 

 they are very full of earthy 

 matter (silica), and one kind 

 (JEqidsetum Hyemale), called 

 Dutch Hush, is so rough with 

 it that it is used for polishing 

 and scraping many articles. 



Horsetail. 



The second division of the vegetable kingdom are the 

 Endogense, which are those plants growing from a central 

 bud only, as the palms, bamboos, and canes of all kinds, the 

 grasses and all graminiferous or grain-bearing plants, as 

 wheat, barley, &c. They have but one cotyledon in the 

 seed and have no bark, but in place thereof a kind of natural 

 varnish or thin coating of silica ; this varnish or external 

 polish is seen in the stalks of corn and on canes. Their 

 leaves are often of great size, the veins run parallel to 

 each other (fig. 8), they often grow from an expanded 

 base which surrounds the stalk as in corn, and branch 

 off at regular intervals making knobs or joints, as may 

 be seen in the bamboo cane (figs. 9 and 10), in other 

 cases they branch off spirally, and when fallen form a 

 sort of trellis- work on the stem (as in some of the palms) but 

 always in a regular manner. The wood of this family of vege- 

 tables has the same porous structure as cane (figs. 11, 12, 

 13, 14), and is often hollow in the centre, becoming more and 

 more solid according to the age of the tree. The stems of 

 these plants are limited in growth and soon acquire their full 

 size, which never exceeds eighteen or twenty inches in dia- 



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