18431862] HOMOLOGIES 273 



gives suspicion that the later.il membranes of the clinandrum Letter 602 

 are the two other and rudimentary anthers, which in Orchis 

 and CepJialanthera, etc., exist as mere papillae, here developed 

 and utilised. 



Now for my question. Exactly in the middle of the 

 filament of the normal anther, and exactly in the middle of 

 the lateral membrane of the clinandrum, and running up to 

 the same height, are quite similar bundles of spiral vessels ; 

 ending upwards almost suddenly. Now is not this structure 

 a good argument that I interpret the homologies of the sides 

 of clinandrum rightly ? x 



I find that the great Bauer 2 does not draw very correctly ! 

 And, good Heavens, what a jumble he makes on functions. 



To J. D. Hooker. Letter 6o3 



Down, Oct. 22nd [1861]. 



Acropera is a beast, stigma does not open, everything 

 seems contrived that it shall not be anyhow fertilised. There 

 is something very odd about it, which could only be made 

 out by incessant watching on several individual plants. 



I never saw the very curious flower of Canna ; I should 

 say the pollen was deposited where it is to prevent inevitable 

 self-fertilisation. You have no time to try the smallest 

 experiment, else it would be worth while to put pollen on 

 some stigmas (supposing that it does not seed freely with 

 you). Anyhow, insects would probably carry pollen from 

 flower to flower, for Kurr states the tube formed by pistil, 

 stamen and " nectarblatt ' secretes (I presume internally) 

 much nectar. Thanks for sending me the curious flower. 



Now I want much some wisdom ; though I must write 

 at considerable length, your answer may be very brief. 



1 Though Robert Brown made use of the spiral vessels of orchids, yet 

 according to Eichler, Bliithendiagramme, 1875, Vol. I., p. 184, Darwin 

 was the first to make substantial additions to the conclusions deducible 

 from the course of the vessels in relation to the problem of the morphology 

 of these plants. Eichler gives Darwin's diagram side by side with that of 

 Van Tieghem without attempting to decide between the differences in 

 detail by which they are characterised. 



2 F. Bauer, whom Pritzel calls "der grosste Pflanzenmaler." The 

 reference is to his Illustrations of Orchidaceous Plants, with Notes and 

 Prefatory Remarks by John Lindley, London, 1830-38, Folio. See 

 Fertilisation of Orchids, Ed. II., p. 82. 



VOL. II. 1 8 



