Chap. IV. NEOTTIA NIDUS- AVIS. 125 



as I have described under Listera ovata. The flowers 

 are frequented by minute Diptera and Hymenoptera. 

 Neottia nidus-avis. — I made numerous observations 

 on this plant, the Bird's-nest Orchis,* but they are not 

 worth giving, as the action and structure of every 

 part is almost identically the same as in Listera ovata 

 and cordata. On the crest of the rostellum there are 

 about six minute rough points, which seem particularly 

 sensitive to a touch, causing the expulsion of the 

 viscid matter. The exposure of the rostellum to the 

 vapour of sulphuric ether for twenty minutes did not 

 prevent this action, when it was touched. The label- 

 lum secretes plenty of nectar, which I mention merely 

 as a caution, because during one cold and wet season 

 I looked several times and could not see a drop, and 

 was perplexed at the apparent absence of any attrac- 

 tion for insects ; nevertheless, had I looked more per- 

 severingly, perhaps I should have found some. 



The flowers must be freely visited by insects, for 

 all in one large spike had their poUinia removed. 

 Another unusually fine spike, sent me by Mr. Oxenden 

 from South Kent, had borne forty-one flowers, and it 

 produced twenty-seven large seed-capsules, besides 

 some smaller ones. Dr. H. Miiller of Lippstadt in- 

 forms me that he has seen Diptera sucking the nectar 

 and removing the poUinia. 



The pollen-masses resemble those of Listera, in 

 consisting of compound grains tied together by a few 

 weak threads ; they differ in being much more inco- 

 herent ; after a few days they swell and overhang the 

 sides and summit of the rostellum ; so that if the ros- 

 tellum of a rather old flower be touched and an explo- 



♦ This unnatural sickly-looking lives; but, according to Irmisoh 



plant has generally been supposed (' Beitnige zur Biologio und Mor- 



to be parasitic on I'he roots of the phologie der Orchideen,' 1853, s. 



trees under the shade of which it 25), this certainly is not the case. 



