A flower may be considered to be a branch whose leaves 

 have become in the course of time very much modified to 

 suit its special functions, and at the same time the branch 

 from which these leaves arise has been so shortened that 

 they appear to be inserted upon a very short space. This 

 portion of the branch is of such importance, and is so 

 variable in shape that it is necessary it should have a 

 name. It is called the thalamus. In many flowers the 

 thalamus is small and of no noticeable development, but 

 the floral circles arise from it one above the other. In the 

 Buttercup, above the stamens, the thalamus forms a con- 

 ical projection, upon which are placed the numerous car- 

 pels. The Raspberry has a similar projection, but here the 

 base of the thalamus is also developed into a small cup 

 upon the edge of which arise the calyx, corolla, and sta- 

 mens. In Strawberry we find the same condition, only in 

 fruit the terminal projection enlarges enormously, bearing 

 the little carpels on its surface. In the Rose the thalamus 

 cup is greatly enlarged, and constricted above to form a 

 hollow chamber, at the apex of which are the calyx, 

 corolla, and stamens. The pistil here consists of numerous 

 free carpels growing within and at the base of the cup. 

 They have long slender styles, bearing small round stigmas, 

 which protrude in the centre of the flower. In Gumtrees, 

 Ivy and Composites the cup is well developed, but inti- 

 mately blended with the pistil, so that the other circles of 

 the flower arise above the fruiting portion. 



In the ovules are produced the large spores; in the 

 anthers the small spores. An embryo is formed only when 

 the contents of a small spore become mingled with that 

 of a large spore. The pollen is blown or otherwise carried 

 from the anther to the stigma; here it adheres. It grows 

 in an elongating delicate tube through the course of the 

 style, and enters the ovarian cavity. When it meets an 

 ovule it enters it and blends with the contained large 

 spore in which now develops an embryo. The ovule under- 

 goes certain changes, which end in what we call the seed. 

 A seed is an embryo plant enclosed in a tough coat, which 

 enables it to remain dormant, still retaining the power 

 of starting into life when placed in a suitable medium. 

 Some seeds retain this power only for a short period ; 

 others for many years. The retention of this power appears 

 to depend largely on the seed coat's resistance to the 

 diffusion of moisture. It appears that in all cases where 

 the embryo loses its contained water beyond a certain 

 degree death ensues. 



