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Link: • Cadwallader Colden to Carl Linnaeus, 20 February 1749 n.s.
Dated February 9th, 1748-9. Sent from Coldengham (USA) to Uppsala (Sweden). Written in English.


You have don me such honour, by your two letters, One of the 6th of August 1747, the other without date by Mr Kalm, that I cannot otherwise account for it, than by your willingness to incourage every attempt to promote knowledge: for I am so sensible of my want of skill in the Botanical science, that I can no way deserve the praises you are pleased to bestow on the little performances I have made. When I came into this part of the World, near forty Years since, I understood only the Rudiments of Botany, & I found so much diffculty in applying it to the many unknowen plants, that I met with every where, that I was quite discouraged, & laid aside all attempts in that way, near thirty Years, till casually I met with your Books, which gave me such new lights, that I resolved again to try what could be don with your assistence. If then I have been able to do any thing worth your notice, it is intirely owing to the Excellency of your method. However, I still find my self at a loss in a fundamental point in Botany, what it is that certainly distinguishes one Genus from an other of other of the same Class, so as not to be in danger of confounding plants of different Genera, by reducing them into one, or by making different Genera of such as are really one. This difficulty I find puzels sometimes the Masters of the Art, by the disagreements in Judgement on that head, which appears among them. I mentioned this to Gronovius, but I have not heard from him since. I am perswaded that if this difficulty can be removed by any method, it may by yours. It is observed, that animals of different genera seldom copulate, unless they be of the next adjoining Genera in the chain of Nature: That tho’ these produce young by their copulation, the breed of these are never capable of continueing their species. So it is observed of the Mule, proceeding from an Ass & Horse. We observe the same of our wild Geese & household Geese. They by copulation produce Young but these never continue their species any further. And yet we have several of the species of houshold Geese, which, to all appearence, differ as much, or more, from each other, than some of them do from the wild Geese. It is likewise certain, that throughout the whole Genera of both Animals & Vegitables, the distinction of the Male & Female organs is every where observed, & that this distinction is necessary, for the propagation of the kind, but what it is, in the one & in the other, that makes it necessary they should be distinct, so that the species cannot be produced by one alone, I know not, nor do I find, that any Philosopher has attempted to explain it. This, which adapts the female of one Species to the male of the other, is not meerely from the sise, shape or number of their respective organs, as is plain in the case of the tame & wild Geese, & the Horse & Ass, but from something else likewise, which I know not. What I would infer from this is, that a perfect Similitude in the figure, number &c. of the Organs of Generation, are not a certain Characterestic of their being of the same Genus: but that something else must be frequently added to distinguish the Genera. You have on your principles made the Aple & the Pear of the same Genus, & yet I am perswaded they are of different, because there is something so different in the nature of the Pear & of the Aple, that a stock of the one is not proper for the cyon of the other, in grafting or inoculation, whereas the Stocks of the same Genus, tho’ of different species, equally serve for the cyons of any other Species, as those of the same species do. We observe the same in different species of Animals, the males of any species equally serve the females of the other.

I did not intend to say that the Zea is not a native of America, if you have seen all that I have wrote to Gronovius on this head you’l evidently perceive, that my intention was otherwise, however I have expressed my self to occasion mistake: On the contrary, We have many different species of it, which, so far as I can Learn, are not in Europe or Asia. From what I have observed of this Plant, I think it necessary to take in the magnitude of the Plant, & the time of Produceing the seed in full ripeness, as a distinction of the different species of this Genus; for, after the most carefull examination, I can discover nothing else to distinguish them, & yet they are certainly distinct species. Give me leave on this occasion to make one observation, tho’ it be a very obvious one. There are some plants & those the most necessary for humane Life, which grow no where but when sowen by mens hands, & in cultivated Lands, such as our Indian corn, or Zea, Wheat, Barly, Rye, &c. That they never were the Spontanious produce of the Earth, without the Art & Labour of Man, otherwise they must be somewhere found growing Spontanious. So the houshold Animals, Dogs, Cats, Dunghill Fouls, &c. seem to have been concomitants to man from the begining, & that they cannot live without him. For the species at least, & I believe, I may venture to say, that the Genera of Houshold Animals are no where wild, but have from the Begining been dependants on man. Man therefore has a natural right over them, whereas we seems to be in a state of war with the other Animals.

As I had but little skill in Botany, when I began first to examine the plants of this Country, according to your method, it is no wonder that I fell into many mistakes: most part of them I afterwards discover’d by [myself] & sent proper corrections to Gronovius, the most material of which I sha[ll] copy for your use. I likewise sent several dryed Plants to him, but they h[ad] the misfortune to be taken by the french. I had directed the packet, in ca[se] of capture, to be delivered to Messrs du Jardin royal a Paris. So that perhaps you may still hear of them.

I have been oblidged for near three Years past to lay aside all Botanical amusements, the publick affairs of this Government having [oblig]ed me to be, during the Summer Season, on the frontiers of this Govern[ment] where we could not go out of the fortifiyed places, during the cruel & Barbarous War with the French Indians, without danger of being surprised by the Sculking ennemy Indians.

I hope now that we have peace, it may be in my power to make som return to the obligations you have laid on me, by sending some dryed plants, as you direct, with such discriptions as I can make of them. I cannot hope for any great reputation from what I do of this kind, but if you think, that my observations or descriptions can be of any use to the publick, you have my leave to make use of them in what ever manner you shall think proper.

I receiv’d the Dissertation you sent by Mr Sandin, & likewise your Fauna swecica, & Flora Zeilanica from Mr Kalm. They are very acceptable, as I could not otherwise have procurd them in this Country. They shall remain with me as tokens of your Esteem for me & which I hope my Children will value after I am gon.

Mr Kalm ariv’d so late last fall in Pensylvania, that the season of the year did not permet him to proceed in his intended voyage. He tells me that he designs for Canada next spring. I hope to see him at my house in his way thither & to have the pleasure of his conversation for some days. It will give me pleasure if I can be of use to him in making his voyage more convenient or safe for him. If you’l please to continue your faveurs of writing to me Mr Collinson of London, with whom you correspond, will take of your Letters to transmit them to me Or if they be sent to Pensylvania & directed to the care of Mr Benjn Franklen, Post Master in Philadelphia; they will come to my hands God praeserve you in health for the benefite of Mankind But before I conclude I must inform you that the title of Summus Praefectus no way belongs to me. I know not what has led you into this mistake I am with great regard

Dear Sr
Your most obedient humble
Cadwallader Colde[n]

Celeberrimo Carolo Linnaeo Archiatro Regiis Sueciae


Cadwallader ColdenColden, Cadwallader
(1688-1776). American. Physician of
Scottish origin, botanist, physicist,
politician. Lieutenant governor of New
York. Correspondent of Linnaeus.
is grateful for two letters from Linnaeus: one of 6 August 1747[Linnaeus to Colden, 17 August 1747Letter L0825], the other without a date [Linnaeus to Cadwallader Colden, [15 October 1747Letter L0861], delivered by Pehr KalmKalm, Pehr (1716-1779).
Swedish. Botanist and traveller,
professor of natural history at
Åbo. Disciple of Linnaeus.
Travelled in North America 1748-1751.
Correspondent of Linnaeus.
. Colden is aware of his limited knowledge of botany, so it must be an ambition to encourage science that explains Linnaeus’s praise for his ”little performances” [Colden here refers to his catalogued collection of plants brought together in the surroundings of his country seat, Coldengham, and communicated to Linnaeus, who published them under the title “Plantae Coldenhamiae"Colden, Cadwallader “Plantae
Coldenhamiae in provincia noveboracensi
americes sponte crescentes,"
Acta Societatis Regiae Scientiarum
(1743, [1749]), 81-136,
(1744-50 [1751]), 47-82.
]. When Colden arrived in this part of the world, almost forty years ago, he understood little of botany. The unfamiliar flora discouraged him from trying to acquaint himself with it. Then, about ten years ago, Colden came across Linnaeus’s books, which changed everything and made him take up botany again. Thus, it is entirely owing to Linnaeus’s method that Colden has achieved anything at all. However, Colden admits that he still has difficulty in what is knowing what is certain to distinguish one genus from another of the same class, and he finds that he shares this problem with many other botanists. He has discussed this with Johan Frederik GronoviusGronovius, Johan Frederik
(1690-1762). Dutch. Naturalist, senator
of Leiden. Linnaeus’s benefactor and
friend. Published Flora Virginica
(1743, 1762) together with John Clayton.
Correspondent of Linnaeus.
without result. Colden has noticed that animals of different genera seldom copulate, and if they do, the offspring are sterile, e.g. the mule. Colden also mentions wild geese and household geese. Colden dwells on another problem: in both animals and vegetables, the male and the female are distinct. What is it that makes this necessary so that the species cannot reproduce by one of them alone? Colden points out that perfectly similar form, number etc. of the organs of generation is not a certain characteristic of their being of the same genus. Something else must be added to distinguish the genera. He discusses apples and pears where he disagrees with Linnaeus.

The maize (Zea) is no doubt a native of America with many different species that are not found elsewhere in Europe or Asia. Colden believes that the various species could be classified according to the size of the plant and when it produces fully ripe seeds. Colden observes that some plants necessary for human life seem to exist only when they are sown by man and cultivated: Indian corn (or maize), wheat, barley etc. are not found growing spontaneously anywhere. Likewise, domestic animals such as cats and dogs seem to have been companions to man from the beginning.

Colden’s limited skill in botany caused him to make mistakes in the examination of plants using Linnaeus’s method. He has corrected most of them and sent the corrections to Gronovius. He will copy this material and send it to Linnaeus. Colden sent several dried plants to Gronovius but they were taken by the French. As he had addressed them to the curators [supposedly mainly to Bernard du JussieuJussieu, Bernard de
(1699-1777). French. Professor of
botany, brother of Antoine and Joseph de
Jussieu. Demonstrator at the Jardin des
plantes. Sébastien Vaillant’s
successor. Uncle of Antoine Laurent de
Jussieu. Correspondent of Linnaeus.
] at the Royal Garden of Paris [Jardin des plantes, ParisJardin des plantes, Paris,
French. The Jardin des plantes was
founded in 1597 to produce flower models
for the manufacturing of tapestry in
Paris. In 1626 it became a garden for
medical and pharmaceutical plants. In
1739 it was again transformed to le
Jardin du roi, where also a natural
history museum was built. Later in the
eigteenth century a zoological garden
and a library were added.
], they might have been taken care of.

For three years Colden has been obliged to lay aside botany. The reason is the war with the French Indians when he had to spend all his time in fortified places.

Now peace prevails so he can take up botany again and send dried plants with descriptions to Linnaeus.

Colden has received the dissertation sent by Johan SandinSandin, Johan (?-1748).
Swedish. Clergyman in New Jersey.
Husband of Anna Margareta Sandin in her
first marriage.
and also Fauna SvecicaLinnaeus, Carl Fauna Svecica
sistens animalia Sveciae regni:
quadrupedia, aves, amphibia, pisces,
insecta, vermes, distributa per classes
& ordines, genera & species. Cum
differentiis specierum, synonymis
autorum, nominibus incolarum, locis
habitationum, descriptionibus
(Leiden 1746). Soulsby
no. 1152.
and Flora ZeylanicaLinnaeus, Carl Flora
Zeylanica; sistens plantas Indicas
Zeylonae insulae, quae olim 1670-1677,
lectae fuere a Paulo Hermanno [...]
demum post 70 annos ab Augusto
Günthero [...] orbi redditae

(Stockholm,1747). Soulsby no. 420.
from Kalm. Colden is very grateful for these books because they are not available in his province.

Kalm arrived in Pennsylvania last autumn, too late to proceed with his intended voyage. He intends to go to Canada next spring. Then Colden hopes to receive him in his home and to be of use to him. If Linnaeus would like to write to Colden, letters can be forwarded by Peter CollinsonCollinson, Peter (1694-1768).
British. Merchant and amateur naturalist
in London, corresponded with many
scientists. Correspondent of Linnaeus.
in London. Letters can also be directed to Pennsylvania in the care of Benjamin FranklinFranklin, Benjamin (1706-1790).
American. Publicist, scientist and
, postmaster in Philadelphia. However, Linnaeus should know that the title of Summus Praefectus does not belong to Colden!


a. original holograph (LS, III, 79-80). [1] [2] [3]


1. A selection (1821), vol. 2, p. 451-457   p.451  p.452  p.453  p.454  p.455  p.456  p.457.
2. The Letters and papers of Cadwallader Colden (1920), vol. 4, p. 95-99 .


MS1 [The manuscript is damaged: readings inserted within square brackets have been taken from ED1 or ED2].