48 FERN ALLIES. 



the summit of the stem, each spore being furnished with 

 four spiral threads attached to its base, which curl and 

 twist about in a very curious way, and move the seed 

 along in various directions. The seeds shaken on white 

 paper and damped, will be seen with the aid of a lens to 

 be crawling about like as many minute spiders. The 

 structure of the stem is very beautiful ; the hollow centre 

 is surrounded by a circle of pipes, and another circle of 

 larger pipes encompasses that, the number of these larger 

 pipes varies in different species, agreeing with the num- 

 ber of leaves in a whorl, these pipes run uninterruptedly 

 through the stem, and you may suck water through them. 

 A great deal of silex enters into the composition of the 

 stem, giving it a remarkable roughness. The plants grow 

 as weeds in watery places, and in arable land. 



When setting forth in search of the various members of 

 this family, the Corn Horse-tail (E. arvense) was the first 

 to greet us. The fertile stems had risen from the ground, 

 bearing large cones on their summits ; their joints fur- 

 nished with ample sheaths, but no branches. It grew 

 among the young corn, in fields where the ground was 

 heavy, ripening its seeds in April. The barren stems 

 were in course of development, sculptured with ten 

 grooves, and bearing from eight to ten branches in each 

 whorl, the branches becoming shorter as the whorls 

 neared the summit. According to Lightfoot, this plant 

 " is troublesome in pastures, and disagreeable to cows, 

 never touched by them unless compelled by hunger, and 

 then bringing upon them an incurable diarrhoea." The 

 root-stem of the Corn Horse-tail extends underground 

 like that of the Brake Fern, making it very difficult to 



