36 Prof. Link on the Structure of the Orchidacese. 



V. — Observations on the Structure of the Orchidacese, particu- 

 larly the Vandea3. By Prof. H. F. Link*. 



Lindley, who has contributed so much to the knowledge of the 

 Orchidacese, gives them the following character in his 'Vege- 

 table Kingdom/ He ascribes to them a trifoliate calyx, a tri- 

 foliate corolla, the third segment of which, the labellum, is of 

 very different form from the other two ; further, three stamens, 

 of which either the two outermost are abortive, and only the in- 

 termediate one bears an anther, or the intermediate one is abor- 

 tive, and the two outer bear anthers ; finally, three divisions of 

 the stigma. In reference to the stamens and the stigma he 

 wholly follows R. Brown. But he directs attention to an ano- 

 maly, relating to the stigma, which consists in the fact that the 

 seminiferous portions of the ovary are not opposite to the lobes 

 of the stigma, but alternate with them, as the seedless portions 

 occur in a line with the lobes ; so that we ought therefore to say 

 that the ovary consists of six carpellary leaves. 



R. Brown came to the idea that the Orchidacese have properly 

 three stamens, from the circumstance that there occurs very fre- 

 quently, especially in the New Holland Orchidacese, on each side 

 of the anther-bearing column, an appendix which represents 

 those stamens. He observes indeed, that those appendices also 

 occur when, from a higher degree of development, three stamens 

 are present, for we have examples of this ; and he does not con- 

 ceal that these appendices are devoid of vessels, but he adds that 

 he does not consider the presence of these as determining an 

 organ. It appears to me however, in opposition to the opinion 

 of this celebrated observer, that the presence of such vessels is 

 indispensably necessary to the determination of an organ. For 

 in all the organs of the Phanerogamia the vascular bundles (of 

 spiral or pseudo-porous vessels, or both together) form the foun- 

 dation of the organ, nay, even determine its form, and there is 

 no organ of any importance without them. In the Naiadese, and 

 if instead of Phanerogamia we use the more definite word Pha- 

 nerophytes, in the Mosses, tubes or elongated cells occur instead 

 of them in the interior of the organ. Prom this it follows that 

 they are the sap-bringing vessels. It is requisite to know there- 

 fore what is the condition of the vascular bundles in the column 

 of the Orchidacean flower, when stamens and style are united. 



Before we enter upon this inquiry, the following remarks are 

 necessary. All botanists, except Linnaeus, make the labellum a 

 division or leaflet of the perigone and of its inner circle, which 



* Extract from a Treatise read before the Berlin Academy of Sciences ; 

 translated from the * Botanische Zeitung,' by Arthur Henfrey, F.L.S. 



