204 LETTER XVII. 



kind of floret is called tubular. The stigmas are two 

 {jig. 7.)> and project beyond the mouth of a little 

 hollow cylinder, which is found at the orifice of all 

 the tubular florets of the disk {fig. 4. a.). At first 

 sifjht you mav be at a loss to determine what the 

 cylinder is : but if you use a magnifying glass, you 

 will presently discover that it is formed of five anthers, 

 which grow together by their edges, in the same 

 manner as petals grow by theirs, when they form a 

 monopetalous corolla. It is easy to slit this cylin- 

 der {fig. 5.), and then you will see that each anther 

 has its filament, and two lobes containing the pollen. 



The broad flat part, out of which the florets grow 

 {fig. 6. a.), is called the receptacle ; it is some- 

 times covered with scales, or hairs, or is even pitted 

 with hexagonal depressions, which look like the cells 

 of honeycomb. Can you guess to what, in other 

 plants, this receptacle is analogous ? for you may be 

 sure it is only some very common part masqued and 

 disguised, to the eyes of an ordinary observer. To 

 imderstand it, you should first compare the flower- 

 head of a composite flower, with an umbel (See 

 Letter IL). In the latter the flowers are all on long 

 stalks, that proceed from a common point, which 

 is the termination of the stem or branch ; their point 

 of origin is wider than the stem itself, because of the 

 number of stalks, for whose bases room has to be 

 found ; the stalks, however, are very slender, and 

 do not occupy much room. But suppose the flowers 

 of an umbel had no stalks, but were seated close upon 

 the stem, as sometimes happens ; it is obvious that as 



