52 Mr. A. Henfrey on the Progress of Physiological Botany: 



above, and the upper part of the tubes thus remains destitute of 

 granular matter or fertilizing fluid, because the latter is always 

 carried toward their lower extremities. To the objection that the 

 tubes are too numerous to be produced from the pollen-grains, 

 the author opposes the fact of the enormous number of granules 

 contained in the pollen-masses; for instance, in Orchis Morio the 

 two principal pollen-masses contain each no less than 200 secon- 

 dary masses ; and the latter, which when compressed divide into 

 granules united in fours, individually present more than 300 

 orifices from which pollen-tubes may be emitted; consequently 

 in all no less than 120,000 tubes may be produced. Again, in 

 Orchis abortiva the moistened point of a needle will take up 

 several thousand of the simple spherical pollen-grains, and in 

 this species the progress of the pollen-tubes along the conducting 

 tissue of the female organ may be easily followed, affording con- 

 viction that the mucous cords are neither more nor less than 

 prolongations of them. 



With regard to changes of relative position of the parts of the 

 ovule in the ovary occurring before the period of fertilization, the 

 author does not consider it worth while in the present day to 

 stop to discuss them, since it is known that in whatever direction 

 the orifices of the coats of the ovule point, the ovules may be fer- 

 tilized by filaments floating freely in the cavity of the ovary. He 

 notices that M. Brongniart found instances of this in Helian- 

 themum niloticum and tegt/ptiacum, without however recognizing 

 the free filaments to be pollen-tubes ; and he himself has seen 

 similar filaments free in the ovary of Cresta gialla*, which pos- 

 sesses no conducting tissue. 



The first researches of Professor Amici on the Oixhidacece were 

 made on Orchis Morio. At the period when the corolla expands, 

 the ovule is so far developed, that the testa, the tegmen and the 

 nucleus, or the primine, secundine and nucleus, may be distin- 

 guished ; the latter consists of a large central utricle inclosed in 

 a layer of smaller cells ; it resembles an acorn, the teguments 

 representing the cupule. 



Subsequently this cellular layer or membrane which clothes the 

 nucleus opens like a tulip, and the nucleus, consisting of a simple 

 cell, remains wholly uncovered, so that a granular fluid collected 

 toward the apex may be seen in its interior. It might be sup- 

 posed that this exposure of the nucleus indicates the fitting mo- 

 ment for fertilization, but this is yet far distant. 



When the flower has begun to wither, a new transformation 

 has taken place in the ovule. The testa and tegmen have in- 



* Cresta gialiu is translated Cockscomb, with a query, by Prof. Von Mohl. 

 In the Ann. des Sc. Nat. it is considered as Rhinanthus crista galli. It 

 seems most probable that Celosia cristata is the plant in question. — Rep. 



