ii22 Home Nature-Study Course. 



(5). Did you find more than one stalk springing from the roots of 

 the Canada Thistle? 



(6). Describe the stalks of both species: are they smooth or spiny? 

 Weak and tender, or upright, strong and woody? 



(7). Are these plants protected by bitter and acrid juices as well as 

 by spines? ■-" 



(8). Do grazing animals eat thistles? 



Facts for Teachers. — The Common Thistle is most often found growing in pas- 

 tures, roadsides and fence corners, where it may remain undisturbed for the neces- 

 sary second year of growth before it can mature its seeds. Cultivation of the 

 soil when it is in first year rosettes is destructive to it, and except that it is so large 

 and so viciously prickly it would not be considered a very bad weed. 



Not so with the Canada Thistle. Its roots are perennial and they invade garden, 

 grain-field or meadow, wherever its seeds are carried by the winds. These roots 

 are what make it so difficult to destroy. They creep for yards in all directions, 

 just deep enough to be sure of moisture, and sending up new plants here and 

 there, especially if the main stalk should be cut off. Roots severed by the plow 

 promptly send up shoots from both of the broken parts. They feel their way around 

 and under rocks and boulders, and if smothered beneath hay and straw stacks 

 creep out on the surface of the ground and show a prickly green and purple fringe 

 about the base. The writer knew of a case in which a Canada Thistle root entered 

 the loose joint of a pipe leading from a spring in a pasture to a drinking trough 

 for cattle. During a summer's growth it crept eighteen feet in search of an outlet 

 before it so clogged the pipe that it had to be taken up and the obstruction re- 

 moved. The Common Thistle has a single main root with many fibrous and 

 clustered branches, all penetrating the soil somewhat deeply but not sending up 

 any family of side shoots. 



The stalks of both species are strong and woody, the Canada Thistle reaching 

 a height of two to five feet, the other being more short and stocky. The Canada's 

 stalk is round and slightly ridged but almost spineless between the leaves, while 

 the other is closely hugged by winged and prickly leaf-stems except for a few 

 inches above the root. 



Grazing horses and cows keep their sensitive noses away from green thistles, 

 but sheep, goats and donkeys are not so particular; the last named animal is re- 

 puted to be fond of the plant, as its juices are sweet and he does not seem 

 to mind the prickles. When cured with the hay the withered plant seems to be 

 acceptable as food, even though not quite so well liked as the smooth sweet grass. 



Lesson VII 



THE LEAVES 



Observations by Pupils: 



( I ) . Do the leaves of thistles grow alternately or opposite each other 

 on the stalk? 



(2). Are they smooth, or hairy, or wooly, on one or both sides? 



