1 126 Home Nature-Study Course. 



an invaluable help in such study and very serviceable ones may be 

 bought for fifty cents to a dollar. 



Observations by Pupils ^ 



(i). Carefully strip away the bracts surrounding the flower-head so 

 that single flowers may be removed, seed and all. Does the " thistle- 

 down " entirely surround the tube of the flower? Is the down as long 

 as the flower-tube? What color is the down? 



(2). Are the silken hairs united at the base or attached singly to 

 the seed? 



(3). How is the floss attached to the seed? 



(4). Is the down fastened to the smaller or the larger end of the 

 seed? 



(5). Hold a thistle balloon between your eye and the light. Does 

 the floss consist of single straight hairs or have they many fine 

 branches ? 



(6). How is the floss arranged when all the flowers are packed to- 

 gether in the thistle-head? 



(7). Take a seed from among its closely packed fellows and put it 

 in the sun or in a warm, dry place where it cannot blow away. How 

 long does it take for the balloon to open out? What is the shape of 

 the balloon? Are there any hairs in the center of the balloon, or are 

 they all arranged in a funnel-shaped ring? Can you find a perfectly 

 spherical thistle balloon with a seed still attached to it? 



(8). Blow the opened parachute from its place. How far was it 

 able to carry the seed with one impulse of your breath? If it fell to 

 the floor, see whether you can uplift and start it onward with another 

 breath. 



Facts for Teachers. — Very beautiful and wonderful is the pappus of the thistle; 

 it is really the calyx of the flower, its tube being the narrow collar into which tlie 

 hairs are unTted at the base, and the limb split up into the silken floss which sur- 

 rounds the purple tube ; in length it reaches only to the fringed lobes of the corolla. 

 At the larger end of the seed is a circular depression with a tiny hub at its center; 

 into this ring and around the knob is fitted the collar which attches the pappus 

 to the seed. Even with the unaided eye one can see, when holding the balloon 

 between the eye and the light, that each hair of the floss is a many-branched plume 

 whose branches interlace and assist to make it more buoyant. 



When first taken from its crowded position on the flower-head, the pappus 

 surrounds the corolla in a straight, close tube, but if placed for just a few moments 

 in the sun, or a dry, warm spot, the threads separate, the filmy branchlets open 

 out and a fairy parachute is formed with the seed hanging beneath; if no breath 

 of air touches it while spreading it will sometimes form a perfect funnel, which 

 seems almost able to balance the seed in the air; when blown upon, some of 

 the silken threads lose their place in the rim and rise to the center. A sharp 



