472 DOCTOR MUHLENBERG [1792. 



No. 4, looks like a Hydrocharis ; but has three stamina, one 

 differing in size and colour from the rest \_Heter anther a reniformis, 

 Ruiz and Pavon]. * * * * 



No. 24. Asclepias tuberosa. I agree with you in opinion, that 

 decumbens and tuberosa are the same plant. I have found it canle 

 erecto et decumbente, foliis alternis et oppositis. 



***** 

 No. 33, is a plant we call Adam and Eve. I think it is not de- 

 scribed by Linnaeus ; and therefore named it, in my Index, Ophrys 

 hyemalis, until better informed ; because the leaves are green all 

 winter. 



I feel, with you, the many difficulties we are under, to come to a 

 certainty, in respect of many plants ; and it gives me some sort of 

 .satisfaction, that your Plantce adversaria* arc, or have been, mine. 

 However, by assisting one another, we may do more. If I have 

 cleared up a single doubt of yours, it shall be great satisfaction to 

 me. By comparing notes we will go on cleverly. 



As soon as I can get time, I will make out a copy of the Index 

 I sent, 1790, to the Philosophical Society. It is printed in the 3d 

 Volume of the Transactions ; but will hardly be published soon. 

 And then I will beg the favour of you, to inform me which plants 

 don't grow with you, and which you don't find mentioned, though 

 you know them to be Pennsylvanians. I would heartily wish to 

 have a general index of such plants as have been already observed 

 in Pennsylvania, or even in North America. Forster's Catalogue 

 is very imperfect. 



Sangiiisorba Canadensis, and 3Ienyanthes trifoliata, both grow 

 with us. Parnassia, I have not seen alive ; but the dried specimen 

 was different from the European. 



You complain that you are a stranger in the Cryptogamia class. 

 I had the same complaint ; but am getting acquainted with these 

 humble and lovely inhabitants of the vegetable kingdom. They 

 enliven my winter excursions, when all the rest of their companions 

 are asleep ; and they have this peculiar prerogative, that if you 

 give them a little water, they will revive, even after a hundred 

 years. In my first setting out, I thought them to be innumerable ; 

 but I find they can easily be counted. I know about half of them, 

 and try to know the rest. If I could only get a sight of Dille- 

 nius's History of Mosses, with copperplates ! Have you no friend 

 that owns the noble work, and could be persuaded to let me have 



