184 



insects. The prominence of the front of the anther-lid has already- 

 been referred to ; be.sides this, the fringe upon the under edge of the 

 lid in front is directed slightly outward, and may assist by becoming 

 entangled or interlocked in the hairs of the retreating insect, and 

 more surely effect the raising of the Hd ; the edges of the column on 

 either side of the stigmatic surface project outward a little, making 

 a shallow channel for the better guidance of the insect toward it ; 

 and it does not seem too fanciful to suppose that the heavy beard upon 

 the labellum, through which the insect must pass with difficulty, may 

 cause it to walk through it as it were on tiptoe, in order to raise its 

 abdomen high above the obstacle, and therefore to strike more surely 

 the stigmatic surface on entering and the anther-lid on retiring. There 

 is besides another curious fact : on raising the lid, it will be seen that 

 it does not open altogether as we should expect it, but is thrust for- 

 ward a little, apparently through some elasticity of the hinge, so that 

 the pollen-masses, when the lid is partially open, are found to reach a 

 position nearly as far forward as the projecting front of the lid did 

 when closed, although on the removal of the pressure it will revert to 

 its original position ; this again seems to lend its aid in the same di- 

 rection. 



Out of nine flowers examined on the first of August at the White 

 Mountains, N. H,, seven had both pollen-masses and stigmatic surface 

 intact ; the other two had each their stigmatic surface smeared with 

 pollen, and the pollen-masses, in one wholly, in the other partially, re- 

 moved. The plant very generally has but a single flower, so that, by 

 what has been stated, it will be seen that, with rare exceptions, no plant 

 is ever fertilized by its own pollen. It is stated by Prof Gray in his 

 Manual of Botany that the Arethusice, to which group Pogonia belongs, 

 aU have the fertile anther like a lid over the column, and that this lid 

 after a time is deciduous ; it may be questioned on this account wheth- 

 er it might not here prove to be directly capable of self-fertilization ; 

 but in one of the plants examined. In which the pollinia had been re- 

 moved, the stigmatic surface smeared with pollen, and the petals of 

 the flower quite withered, the lid still remained, and no loss of elasti- 

 city in the hinge was noticed, so that the anther probably does not fall 

 oflf till a period subsequent to the fertilization of the plant. In anoth- 

 er plant not yet showing any signs of decay, where the pollen had 

 been partially removed, that which remained was much discolored, 

 and even seemed to show signs of decay, as if but a temporary ex- 

 posure to the atmosphere were injurious to it. 



This Orchid agrees more nearly with Dendrohium chrysanthum than 

 with any other mentioned by Darwin, but difiers peculiarly from that 



