8i6 



PHENOMENA OF SEXUAL REPRODUCTION. 



slightly against the rostellum, and again withdrawn slowly in this position (Z)), the viscid 

 mass of the rostellum or adhesive disc of the pollinia to which the pollen-masses are 

 attached, remains sticking to the pencil. The pollinia are now completely removed from 

 the two anther-lobes by the withdrawing of the pencil, as is shown in E and F. If the 

 pencil with its pollinia attached is now again inserted into another flower in the direction 

 of the bottom of the labellum, the pollinia necessarily come into contact with the viscid 

 stigmatic surface and adhere firmly to it ; when the pencil is again withdrawn they are 

 left behind, being partially or entirely torn from the pencil. In consequence of the form 

 and position of the parts of the flower, an insect which settles on the anterior part of the 

 labellum would in the same mianner be able to creep into the bottom of the nectary with- 

 out disturbing the rostellum ; but when it again crept out after obtaining the nectar, it 



YlQ,. \'o\.—Epipactis latifolia: A longitudinal section through a flower-bud; B open flower after removal 

 of the perianth with the exception of the labellum / ; C the reproductive organs after removal of the perianth 

 seen Irom below and in front ; Z> as -5, the point of a lead-pencil b inserted after the manner of the proboscis of 

 an insect ; E and F the lead-pencil with the pollinia attached ; fK ovary, I labellum, its bag-like depression 

 serving as a nectary, n the broad stigma, oi the connective of the single fertile anther,/ pollinia, h the rostellum, 

 X X the two lateral gland-like staminodes, i place where the labellum has been cut off, s the columnar style. 



would strike against it and carry off" the pollinia ; and on crawling into a second flower, 

 these would come into contact with the viscid stigma, and would remain attached to it. 

 In some other Orchideae the contrivances are much more complicated. 



Sect. 32. — Hybridisation ^ In the preceding paragraphs we have spoken 

 only of the union of the reproductive cells of the same plant, or of two individuals of 

 the same species. We learn however from experience that a fertile sexual union can 



^ J. G. Kolreuter, Vorlaufige Nachricht von einigen das Geschlecht der Pflanzen betreffenden 

 Versuchen u. Beobachtungen, Leipzig, 1761; Appendices in 1763, 1764, and 1766. — W. Herbert, 

 On Amaryllidaceoe, with a treatise on cross-bred vegetables; London, 1837. — Gartner, Versuche u. 

 Beobachtungen iiber die Bastarderzeugung im Pflanzenreich ; Stuttgart, 1849. [See notice by 

 Berkeley, Journ. Roy. Hort. Sec. vol. V, 1850, p. 156.] — Wichura, Die Bastardbefruchtung im 

 Pflanzenreich, erlautert an den Bastarden der Weiden (with two nature-printed plates) : Breslau, 

 1865. [See abstract by Berkeley, Journ. Roy. Hort. Soc. new series, vol. I, 1850, p. 57.] 



