II COMPOSITE 247 



be different in different parts of the tissue, for if a stamen 

 hi cut vertically it at once rolls up. When the pistil is 

 full grown, and the stigmas open, the stamens lose their 

 power of contraction.^ 



0. nigra (Knapweed). — According to Knuth ray 

 flowers are always wanting ; in England they occur, 

 though not generally, yet not infrequently. Hairs are 

 few and small ; the leaves are rather cottony underneath. 



0. Scabiosa. — A stouter plant than the preceding, 

 which, however, it much resembles. The flower-heads 

 always have an outer row of longer, sterile flowers. 



C. Cyanus (Corn-flower). — A corn-fleld weed. It is 

 covered with a loose cottony down. 



C. Oalcitrapa. — A rare plant, found in dry waste places 

 in the South of England. It is sometimes covered with 

 loose cottony down ; as is also C. solstitialis, a rare plant, 

 found in fields in the East and South of England, but not 

 native ; it is a native of the Mediterranean area which 

 has become widely naturalised. 



Tragopogon 



The leaves are long and grass-like. Achenes narrowed 

 at the top into a long beak, and bearing a pappus of 

 feathery hairs. We have one species, T. pratensis, 

 with yellow florets. T. porrifolius, which has purple 

 florets, occasionally occurs as an "escape." 



T. pratensis (Goat's-beard, John-go-to-bed-at-noon). 

 — The heads contain 20-50 golden-yellow florets. They 

 close in wet weather, and about noon, whence the name. 

 At Upsala, according to Linnseus, they open at 3 to 5 in 

 the morning and close as early as 8 to 1 0. The plant is 

 glabrous. 



Helminthia 



Characterised by the outer bracts, which are leafy 

 and broadly cordate. The achenes are narrowed into a 

 short beak. 



^ Colin. "Ueber contractile Gewebe im Pflanzenreiche, " Jahresh. SehlesiscTien 

 Ges. 186L 



