Flowering and its Results. 115 



The calyx of the grasses is called a glume, from a Latin word, 

 meaning a husk. Fig. 9 shows this— A, is the glume ; B, the 

 arista or awn. In the oat and wheat this forms the chaff, which 

 is used for various purposes of stuffing ; these are considered by 

 some as only membranous bracts. These awns are sometimes 

 employed as hygrometers. To do this, Comstock directs that 

 the middle part of the awn, which is twisted or formed like a 

 screw, must be used, one end of it to be cemented to the centre 

 of a circular plate, which is marked off into degrees ; to the other 

 end, a bristle, to serve as an index, must be attached. The 

 whole being covered with a glass, forms a hygrometer or mois- 

 ture measure. When the weather is damp or rainy, the awn 

 untwists and moves the hand in one direction, but as the atmo- 

 sphere becomes dry it ceases at first to move, and then turns in 

 a contrary direction. The moisture of the hand will set these 

 awns in motion, making them appear like living animals. 



Calyptra, a cap or hood, is the kind of calyx found only 

 among mosses. Fig. 7th shows the fructification of a moss. 

 A, the Calyptra. It is a veil of a conical shape, resembling a 

 thimble. 



The Volva, or wrapper, of a mushroom, is shown in fig. 8. A 

 is the volva. As the plant grows and becomes larger, it bursts 

 its wrapper, which remains around it in the form of a ring, as 

 seen in our figure. m 



Fig 11, at A, shows a Bractea accompanying the flowers of 

 the Tilia. 



Inflorescence, as Lindley observes, signifies the ramifica- 

 tion of that part of the plant intended for reproduction. It has 

 various methods of flowering distinguished by different names, 

 of which we shall mention a few ; and first, an Umbel. This 

 is produced when several peduncles or flower-stems proceed 

 from a common centre, in a whorl, like the braces of an in- 

 verted umbrella, and reaching the same height, form nearly a 

 level head of flowers. Carrot, dill and fennel are examples of 

 this. Fig. 10 shows a compound Umbel. A, the universal 

 Umbel ; B, the Umbellula or partial Umbels ; C, the universal 

 Involucrum, which wrapper is so called when it belongs equally 

 to the whole of an aggregate flower ; D, the partial Involucrum 

 enclosing several sets of florets. 



An Amentum is an assemblage of flowers, composed of scales 



