136 Flowers and their Unbidden Guests. 



whicli is discliarged in not a few species of plants, and 

 especially in many of our Alpine saxifrages, from 

 special organs on the edges of the leaves, is not with- 

 out its functional significance. For the purposes how- 

 ever of the present inquiry we are concerned with no 

 other secretions than such as are resinous, mucilaginous, 

 sweet, or saccharine. These terms, resinous, mucila- 

 ginous, sweet, and saccharine, indefinite as they may 

 sound, miist nevertheless as yet be employed, inasmuch 

 as they furnish the best basis for a division of these 

 glandular bodies into groups ; and, so far as nomencla- 

 ture is concerned, that division seems to me the most 

 acceptable by which the glands that secrete resin, 

 bassorin, and the mixture of mucilage and resin known 

 as blastocol, are called colleters, while those which 

 discharge a sweet-tasting saccharine fluid are called 

 nectaries. It may be accepted as a very general rule 

 that the latter are developed within the flowers, the 

 former on the leaves. But no rule is without excep- 

 tion, and plants are not wanting which have nectaries 

 on their leaves. The number of these plants appears, 

 indeed, to be by no means large; at any rate, up to 

 the present time few such cases are known ; but the 

 possibility always remains that further investigations 

 may discover many more. Those which have been 

 longest known are : Viciafaba, Y. sepium, and F. sativa, 

 Acacia longifolia, Prunus avium and P. laurocerams, 

 Gatalpa syringcefolia, Impatiens tricornis, Ricimis; Vihwr- 



