£,6 NATIVE BRITISH ORCHIDACEiE 



were left severely alone, and produced no seed-capsules, whereas Goodyera in the same 

 house was extremely well pollinated. An attempt to fertilise S. Koman^offima by 

 artificial pollination also failed. This seems to show that the necessary msect was 

 absent, and that, in spite of their marked fragrance, the flowers were unattractive 



to local insects. 



If a pencil is inserted into a flower, the viscidium adheres to it, and is withdrawn, 

 with the attached poUinia, without difficulty. These lie horizontally on the upper 

 surface of the gland, and as the latter, which is long and narrow, adheres longi- 

 tudinally to the insect's proboscis, the pollinia are ahready in position to touch the 

 stigma of the next flower visited, so that no downward movement occurs after 

 removal. Wlien the flower first opens the column lies close to the trough of the lip, 

 and only the tips of the pollinia and the brown front of the anther, on the upper side 

 of the column, are visible. There is only room to insert a bristle beneath the column, 

 but that is sufficient to remove the pollinia. Later the lip turns more downward, 

 and the column moves back from the lip, when the //W^r-surface of the rostellum 

 with its brown viscid gland becomes visible, pointing upwards. If at this stage a 

 finely pointed pencil bearing pollinia is thrust gently into the flower, it readily reaches 

 the stigma, and fragments of pollen at once adhere to it. If the flower has not been 

 previously visited, its own viscid gland adheres to the pencil, wliich brings away a 

 new pair of pollinia affixed to the remains of the first one. 



Mr Henry Mousley, of Montreal, Canada, took the following insects visiting the 

 flowers of S. Kowant^ffiana (the first-named with the poUinia of that species attached 

 to its head), atHatley, Quebec: Chlorhalictus smilacini^oh. ?, Halictes provancheri.^ In 

 August, 1926, he took Bomhis vagans F. Smith at the same place, also bearing pollinia. 



Sub-tribe LI ST ERIN JE 



Rostellum small, tongue-Hke, membranous, sensitive, explosively ejecting on being 

 touched two drops of very adhesive fluid, quickly solidifying and cementing the 

 pollinia to the touching insect's head. 



KEY TO GENERA 



1. Plant green, leaves two, broad, nearly opposite. Listera 



2. Plant brown, leaves none. Neottia 

 Though sometimes included in the Spiranthin^, Ustera and Neottia have nothing 



in common with Spiranthes, being the embodiment of a totally difl'erent idea, unique 

 in the Orchidaceje. The floral mechanism is the same in both, but owing to the 



