Teacher's Leaflet. 



1 125 



the tube anthers and the corolla, the 

 tiny lips open to receive the pollen 

 that is brought by the winged visitors 

 from other flov^^ers. Long and patient 

 observation has convinced botanists 

 that plants whbse flower-parts are so 

 adapted that they cannot be fertilized 

 by their own pollen are much more 

 hardy than those which can be self- 

 fertilized. 



But the canny thistle has let slip 

 no advantage; its flowers must be 

 cross-fertilized and are loaded with 

 nectar to secure for that purpose the 

 services of the long-tongued butter- 

 flies and bumble-bees ; the latter 

 seem to get fairly tipsy as they guzzle 

 the abundant sweet. When the writer 

 w-as a child at school, it was our 

 habit in " thistle-btow time" to strip 

 the bracts from newly opened heads, 

 tear the whole company off flowers 

 from its receptacle and chew them as 

 we would a lump of taffy. 



The thistles believe in large families. 

 The writer has counted the seeds in a 

 single head of the Lance-leaf and they 

 number 116. The seeds are oblong, 

 pointed little nuts or achenes with 

 hard shells. Goldfinches are very fond 

 of them and are often called " thistle- 

 birds" because of their habit of tilting 

 on thistle-heads while eating the seeds 

 and gathering the down, of which 

 they build their nests. 



Lesson IX 



THISTLE BALLOONS 



Purpose. — To bring to the at- 



tentive HQtice of the pupils what 

 power for wide dispersal of its 

 kind is possessed by this vicious 

 weed, and the need for early ac- 

 tion in the atteinpt to drive it 

 from the soil. 



Material. — Blossom of the Common Thistle are best for this lesson, 

 as its pappus is larger than that of the Canada Thistle. A lens is 



The Canada Thistle. 



