Prof. Link on i/te Structure of the Orchidacese. 39 



s were made on Cypripedium spectabile, as the commonest 

 species in our gardens. When we examine a transverse section 

 of the column, it may readily be imagined that the two anthers 

 are actually separate. There are three vascular bundles around 

 the stigmatic canal, and besides these, another above and one on 

 each side, as if belonging to two anthers. But we see just the 

 same in Calanthe veratrifolia , to which we certainly cannot ascribe 

 two separate anthers. As a general rule however, there exist 

 other vascular bundles besides the three situated around the 

 stigmatic canal ; these have already been spoken of. 



In regard to the stigma, there is no doubt that we must, v^^ith 

 Robert Brown, call it three-lobed. In every transverse section 

 made through the column, we find a triple excavation of the 

 stigmatic canal. These excavations are often divided again. Thus 

 we find it in Gongora maculata, of which I have given a mag- 

 nified representation in the Anatomical Plates (Heft i. tab. 20) ; 

 also in Stanhopea eburnea and Maxillaria macrochila, &c. Lind- 

 ley^s view that the capsule is composed of six carpellary leaves is 

 confirmed by transverse sections at the apex of the germen. 



I have nothing new to add to what I formerly made known 

 relating to the remarkable structure of the germinating embryo 

 (Select Anatomico-Botanical Plates, part 2. pi. 7) ; and I still 

 believe that the embryo is not a tuber, in its rudimentary con- 

 dition, but is nevertheless formed in an analogous manner. 



It might be said that the formation of tubers is an especial 

 peculiarity of the Orchidacese, for when the roots are not tuber- 

 ous, the stem strives to become so. The pseudo-bulbi, as Lind- 

 ley calls them, are tuberously-developed internodes. The in- 

 ternal structure is the same as in the stem of Monocotyledons in 

 general ; woody bundles are situated in a circle in a loose paren- 

 chyma ; only here, from the thickness of the internode, there are 

 more circles than is usual elsewhere. A speciality occurs in 

 these. Each woody bundle is composed, as usual, internally of 

 spiral vessels, on the outside of which lie pseudo-porous vessels ; 

 to these follow pseudo-porous parenchymatous cells which be- 

 come successively narrower, and at last appear as prosenchyma- 

 tous cells j at the outside, where the larger parenchyma begins, 

 lie the tubercular tubes of which I will speak immediately. To- 

 ward the interior, near the axis of the tuberous internode, we 

 find the same series, only the pseudo-porous vessels are wanting. 

 Those tubes which I have mentioned are relatively rather wide, 

 without transverse septa, so far as I have examined, and, at re- 

 gular intervals, stand elliptical papillae surrounded by a rim of 

 the same form. At first sight they appear like the common so- 

 called pores or bright spots, but they project distinctly from the 

 front of the tubes, and are more or less filled with a dark gra- 



