564 Handbook of Nature-Study 



outer rows first mature and protrude their pistils; the pollen grains 

 are white. In each flower, the corolla is tube-shaped and purple, part- 

 ing into five fringelike lobes at the top, and fading to white at its 

 nectar-filled base. 



The stamens have dark purple anthers, united in a tube in which 

 their pollen is discharged. The pistil, ripening later, shoves out the pollen 

 with its stigma, which at first is blunt at the end, its two-parted lips so 

 tightly held together that not a grain of its own flower's pollen can be 

 taken. But when thrust far out beyond the anther-tube, the two-parted 

 stigma opens to receive the pollen which is brought by the many winged 

 visitors; for of all flowers, the thistles with their abundant nectar are the 

 favorites of insects. Butterflies of many species, moths, beetles and bees 

 — especially the bumblebees — are the happy guests of the thistle blooms. 

 The thistles believe in large families; a single head of the lance-leaved 

 thistle has been known to have 116 seeds. The seeds are oblong, pointed, 

 little akenes, with hard shells. Very beautiful and wonderful is the 

 pappus of the thistle ; it is really the calyx of the flower, its tube being a 

 narrow collar, and the lobes are split up into the silken floss. 

 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 attaches the down to the seed. Hold 

 the balloon between the eye and the light, and it is easy to see 

 that the down is made of many-branched plumes which inter- 

 lace and 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, the threads spread, the filmy branchlcts 

 open out, and a fairy parachute is formed, with the seed hang- 

 ing beneath ; if no breath of air touches it while spreading, it 

 will sometimes form a perfect funnel ; when blown upon, some 

 of the silken threads lose their places on the rim and rise to the 

 center. When driven before the breeze, this balloon will float 

 for a long distance. When it falls, it lets go of the seed as the 

 wind moves it along the rough surface of the ground, and when 

 A flnretfromit is thus unburdened the down flufiis out in every direction, 



a iliistte making a perfect globe. 

 pmver-head. -poT the first season after the seed has rooted, the thistle 

 develops only rosettes, meanwhile putting down roots and 

 becoming permanently established. The next season, the flowers and 

 seeds are developed, and then the plant dies. Would that this fact were 

 true of the Canada thistle; but that, unfortunately, is perennial, and its 

 persistent roots can only be starved out by keeping the stalks cut to the 

 ground for the entire season. This thistle trusts to its extensively creep- 

 ing rootstocks more than to its seeds for retaining its foothold and for 

 spreading. While it develops many seed balloons, a large number of its 

 seeds are infertile and will not grow. 



LESSON CXL 

 The Common, or Lance-leaved, Thistle 

 Leading thotight^The thistle is covered with sharp spines, and these 

 serve to protect it from grazing animals. It has beautiful purple flowers, 

 arranged in heads similar to those of the sunflower. 



