412 ANGIOSPERMAE—MONOCOTYLEDONES 



entering the flower they do not touch the rostellum. They only come into contact 

 with this when creeping back, as the lower part of the labellum has sprung upwards 

 again in the meantime. The insects then remove the poUinia on their heads or 

 backs, and on visiting another flower deposit them on the stigma and so effect 

 crossing. 



Visitors. — W. E. Darwin (Isle of Wight), beside the honey-bee, which is the 

 regular pollinator, observed flies (Sarcophaga carnaria Z., and Coelopa frigida Fall.) 

 and a fossorial wasp (Crabro brevis v. d. £.). 



2637. E. latifolia All. (Darwin, op. cit., p. 100; Kirchner, 'Flora v. Stuttgart,' 

 p. 177; MacLeod, loc. cit.; Kerner, 'Nat. Hist. PL' Eng. Ed. i, II, pp. 253-5; 

 Webster, ' Fertlsn. of Epipactis latifolia ' ; Knuth, ' Bloemenbiol. Bijdragen.') — This 

 species bears wasp flowers. It occurs in two forms : (a) viridans Crantz, with 

 a broad, ovo-cordate, reddish-violet labellum, the raised parts of which are smooth, 

 or slightly furrowed, or altogether absent ; (1^) varians Crantz ( = E. viridiflora 

 Reickb.), with an ovate labellum, reddish in colour with white spots, of which the 



raised parts are indistinct, 

 , a. usually smooth, and some- 



smaller, and possesses no 



Fig. 381. Epipactis latifoha, All. {SLiicT 'D;irx\n). Flower from ioint but is fastened firmly 

 the side, after removal of the perianth leaves, except the labellum 



(enlarged), a, anther ; /, labellum ; r, rostellum ; j, stigma. to the basal legion. In Cor- 



respondence with this the 

 rostellum projects still further beyond the stigma. Automatic self-pollination is 

 therefore excluded, but Webster says that insect visitors effect self-pollination more 

 frequently than crossing. 



Visitors. — These are almost entirely wasps : — Darwin records Vespa sylvestris 

 Scop. ; Kerner, V. austriaca Pz. ; and Knuth, V. vulgaris L. ; Loew (Brandenburg, 

 ' Beitriige,' p. 42) V. rufa L., 5, skg. Webster observed humble-bees as well as 

 wasps. Gerstacker (central mountains of Germany) and Schletterer (Tyrol) saw 

 Bombus hortorum L. 



Hermann MuUer asserts ('Fertlsn.,' p. 532) that E. viridiflora lieichb. (=E. lati- 

 folia All., var. {a) varians Crantz (cf. Ma.x Schultze, ' D. Orchid. Deutschlands, 

 Deutsch-Oesterreichs u. d. Schweiz,' Gera, 1894) has entirely lost the advantages 

 of a viscid rostellum ; only minute pollen-clumps can occasionally be carried away 

 by small insects on this account, and autogamy consequently takes place to a still 

 larger degree than in the next species (E. microphylla). 



2638. E. microphylla Sw. (Darwin, op. cit., p. 102 ; Herm. Muller, 

 ' Fertlsn,,' p. 532.) — Self-pollination takes place regularly in this species, though 

 crossing may also be effected by insects, a part of the pollen adhering to the visitor 

 by means of the mucilage contained in the rostellum. 



