85 



greatest expansion, therefore, being lateral, and by a lateral flat- 

 tening I mean such a flattening as would be produced by a 

 lateral pressure, the greatest expansion being vertical. I also 

 remarked that one of the most prominent of the American botan- 

 ists now living understands by these terms exactly the reverse. 



From another letter from Mr. Ames I find that he has inter- 

 preted the terms in the meaning in which Dr. Britton and I used 

 them. A little closer study of Hooker's and Gray's descriptions 

 made me see that Mr. Ames was correct in claiming that they 

 understood the two species differently from us. Where is the 

 trouble ? As the results of my attempts to answer this question 

 may be of general interest, I give them to the readers of Torreya, 

 hoping that they will kindly help in throwing light upon certain 

 unknown facts concerning the yellow lady's-slippers. 



The large yellow lady's-slipper, Cypripedium hirsutum of 

 the Illustrated Flora and Britton's Manual, I have seen twice in 

 the living state, once many years ago in Michigan and once in 

 New York. As I know it, the lip is low and broad, i. e., flat- 

 tened vertically. Cypripedium pubescens was described by Will- 

 denow in his Species Plantarum, 4 : 143. 1805. He afterward 

 published an excellent figure in his Hortus Berolinensis, I : pi. 

 1 j. This figure shows the low and broad lip, and shows that it 

 is the same as the plant described in Britton's Manual as Cypri- 

 pedium Irirsutum Mill. Miller has no plate, but there is no 

 doubt in my mind that his Cypripedium hirsutum is the same as 

 Willdenow's C. pubescens. Of the latter there is also a fine illus- 

 tration in Barton's Flora, 3 : pi. J+. This also shows the broad 

 lip. The figure published in Sweet's English Flower Garden, pi. 

 71, does not belong to this species, but to what I have regarded 

 as Cypripedium parznflorum. 



The specimens of C. hirsutum or C. pubescens in our herbaria 

 apparently all have a broad lip, so far as one can judge from 

 pressed specimens. 



The small yellow lady's-skipper I have not seen in the living 

 state in the east ; but the plant that has gone under that name 

 in the Black Hills of South Dakota and in the Rocky Mountains 

 is well known to me. In this the lip is taller and narrower, i. c, 



