NECTARIES. 267 



petal is thus extended backwards, and curious ap- 

 pendages {nc, B, Fig. 53) on two anthers pass into 

 the cavity provided, and there secrete a sweetish fluid. 

 Perhaps no flower presents equal advantages with 

 this to the microscopic tyro who would study the 

 structure of the nectary, and the cells (nectar cells) 

 which yield the secretion ; for not only are these large 

 (nc, A), characteristically sugar-loaf-shaped, and promi- 

 nent, but they lie on the outside of the process (their 

 protection being derived from the covering afforded 

 by the spur-like petal previously mentioned), and, 

 consequently, the difficulties of section cutting are, 

 in this case, altogether avoided. The nectar-producing 

 tissue is usually made up of small, thin-walled cells, 

 containing abundant protoplasm, a nucleus, and cell 

 sap, rich in sugar. Often the nectary shows a number 

 of pores, or stomata, on the surface-layer of the cells 

 which line it, and through these the nectar is poured 

 on to the face of the organ, whence it may be 

 sucked up by the visitors to the flowers. Where 

 pores are absent, the covering membrane is extremely 

 delicate, permitting either free transudation, or yield- 

 ing at once, as in some orchids, to the abrading 

 action of the insect tongue. 



Returning to our pelargonium (Plate VIII.), selected 

 because it is at command in most places, and at 

 every season of the year, we find, running down the 

 flower stalk, and immediately under the uppermost 

 and broadest sepal, an enlargement of the stalk itself, 

 marked off by inconspicuous grooves, and terminating 

 in a small bulbous expansion a little below the line 

 b (A), and which is often purplish in colour. This is 



