1^8 ASTER PATENS. SPREADING ASTER. 



and that modern botanists have generally dropped the name of 

 Star- wort. 



Our knowledge of the true Asters has increased wonderfully 

 during the past century. Linnseus, in his first great work, " Hon 

 tus Cliffortianus," in 1737, describes only nineteen species. Will- 

 denow, in his "Species Plantarum," has one hundred and three. 

 Decandolle, in 1836, described one hundred and fifty, after 

 placing a number of Willdenow's species in other genera. Since 

 that time, by the labors of botanists in America, Australia and 

 elsewhere, the number known is over two hundred, the greater 

 proportion of them being natives of the American condnent. 

 The list is sdll increasing, and scarce an expediuon of any con- 

 sequence explores the comparatively unknown portions of the 

 country without adding a new Aster to our list of native flowers. 

 There are few genera of plants better known to the people gen- 

 erally than Aster, and it is not uncommon for the whole of the 

 very large natural order of Compositor to be referred to as the 

 Asicraccous one. 



At first sight, all asteraceous plants seem to have a general 

 resemblance, and, therefore, the order seems one difficult to study ; 

 but with a good pocket lens to examine the inflorescence carefully, 

 the family soon becomes an enticing one to the student. Now 

 every one understands that what is known as the head in a com- 

 posite plant is reahy made up of innumerable small flowers. 

 Sometimes these flowers are few in a head, say less than ten; but 

 to be an Askr there must be more than this number. Then 

 some composites have all the florets alike, but an As/cr must 

 have the outside or ray florets strap-shaped, and the inside or 

 disc flowers tubular; and besides, these strap-shaped outside 

 florets must be fertile, while in other genera they may be barren. 

 The scales of the involucre, or the litde green processes cm- 

 bracing the flowers, are often in one single row ; but in an Aster 

 there must be several rows, and they must lap over one another 

 like tiles on a roof Then again, in some compound flowers the 

 part which bears the little flowers, the receptacle, is elevated, or 



