ON COMPOUND FLOWERS. 219 



to the China Aster : what I have hitherto told you relates 

 more to the mode of flowering ; but we will examine the 

 structure of the flowers themselves. [Plate III.] Look 

 at one of those little yellow florets in the centre of the 

 head : with the assistance of this magnifying-glass you 

 will be able to follow me as I describe the different parts. 

 Observe, first, this white spot, which forms the basis of 

 the floret : it consists of the tube of the calyx, and con- 

 tains the ovary or seed-vessel to which it adheres. 



Caroline. The external part of this tiny tube, then, is 

 the calyx, and the internal part the ovary ; but what are 

 those little hairs which crown the tube, and grow from 

 either the calyx or the ovary, I know not which ? 



Mrs. B. They proceed from the margin of the calyx, 

 which assumes this singular appearance, because its nat- 

 ural growth, in the form of sepals or leaves, is impeded 

 by the pressure of the adjacent florets. 



Emily. And I conceive that the calyx may be stint- 

 ed in its growth for want of food, as well as for want of 

 room. 



Mrs. B. That may also produce some effect in check- 

 ing its growth ; but the elongated form, which the edges 

 of the calyx assume, must be chiefly owing to pressure. 

 In some heads in which the florets are not so crowded as 

 in the China Aster, the calyx wears a more natural ap- 

 pearance, being shaped like a cup, and is of a membran- 

 aceous texture : in others it resembles small scales : in 

 the present instance, and in most compound flowers, it 

 consists of a species of hairs, either separate or glued to- 

 gether. It was formerly considered by botanists rather 

 as an appendage to the calyx than forming a part of it, 

 and was distinguished by the name of tuft orpappus, and 

 though this name applies literally only to hairs, it has 

 been extended by analogy to all the various forms which 

 this organ is capable of assuming. 



Caroline. But this little feathery tuft appears much 

 more ornamental than useful : it cannot, I think, in such 

 a form, afford protection to the flower. 



. | 



1199. How does the China Aster appear as examined by a magnify- 

 ing glass 1 ? 1200. What question does Caroline ask concerning the 

 tube of the calyx 1 1201. How does Mrs. B. answer it? 1202. 

 In different heads how does the calyx appear? 1203. How was it 

 formerly considered by botanists? 



