52 Scientific Proceedings, Royal Dublin Society. 



dislocated the anther does not fall forwards and block tlie entrance to tlie 

 passage ; yet in none of these species was self-pollination effectual. In 

 D. lasioglossum [?) one flower was self-pollinated without result; three flowers 

 of D. draconis were self-pollinated also witliout result, while two flowers of tlie 

 same species which were cross-pollinated produced good capsules ; two 

 flowers of D. formosum were self-pollinated without result. 



Bendrobium parcion Eeichb. f. — In these species the flowers are small ; the 

 lip stands out horizontally much below the top of the column ; no passage is 

 formed between the lip and the column ; the column is not horizontal, but 

 nearly erect. The filament is very elastic, so much so that when the anther 

 is dislocated, it jerks the latter strongly downwards on to the stigma. The 

 anther then remains adherent to the stigma, preventing further access to 

 tliat organ. Five flowers of this species were self-pollinated without the 

 formation of a capsule ; one flower which was cross-pollinated formed a good 

 capsule. 



Dendrobium secundum Lindl. — In this orchid the lip is small, and closely 

 parallel to the column ; the sides of the lip are turned up, and partially 

 embrace the column, forming a narrow passage (see PI. VI., fig. 4). On the 

 roof of tills passage is the rather deeply concave stigma. The anther has a 

 short non-elastic filament ; when dislocated, it is prevented by the up-turned 

 sides of the lip from falling down and blocking the entrance to the passage- 

 The filament is so slender at its insertion into the anther tliat the latter is 

 very easily knocked off. The pollinia, whioli are nearly black, adhere more 

 firmly to the object, by means of which they are removed, than in the case 

 of any other species of Dendrobium examined by me. The posterior border 

 of the rostellum forms a stiff forked plate, projecting backwards and down- 

 wards. The whole rostellum is fixed, and not hinged on the upper border of 

 the stigma, as is the case in D. Dalhonsieamim. The flowers grow in a dense, 

 short raceme. On examining one of these racemes, which is in full bloom 

 and which is being frequently visited by insects, it may be seen that the 

 older flowers towards the base of tlie raceme have lost their anthers, the 

 most recently opened flowers alone retaining their anthers. If a young 

 flower be taken, its pollinia removed, and then an attempt made to insert 

 the pollinia into its own stigma, it will be found quite impossible to do so 

 owing to the narrowness of the entrance to the stigma. On examining an 

 older flower, it will be seen that the stigma has widened considerably, so that 

 the pollinia can enter with ease. If the pollinia be removed with a fine 

 style from a young flower, and introduced into one of the older flowers with 

 a wide stigmatic cavity, it will be found that, on withdrawing the style, the 



