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Letter from Prof. Buckman. Dec 1. 57

In answer to queries in Gardeners Chronicle no 45 – 1857.

Gives no evidence that foreign seed of indigenous weed is more prolific - except probably for good of change of seed – so do not quote him. Ch V

Is inclined to Believeto Believe that many agrarian weeds are result of culture, like the cultivate plants character.

He views Avena sativa as derived from A. fatua; but this again is modified form & as not from wild.

In my note to Buckman, I suggest that agragian & road-side plants are so much acclimatized or accustomed to their new & unnatural peculiar habitats, that native seed of corn Poppy from Sicily probably wd not succeed so well, as our seed,— If this is true in several cases. (as Charlock), then we can understand why there shd have been introduced into America & not in reverse direction.

-Buckman as all other was much struck with rules of introduced weeds into America –

He states that several

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as Bromus secalinus, Sinapis nigra, Chrysanthemum leucanthemum are twice as high as European specimen Agrarian cultivated land in U.S is affected by same weeds with few exceptions as with us.

(answers)

Sinapis nigra introduced in Farms about 7 years ago; before that only an occasional plant & S. arvensis from years before chiefly pest of land; but now the latter much get under partly from good farming in the flax field, when it was first introduced, the S. nigra consistently comes up in quantity, where S. arvensis is there now the exception.

In poor meadow Brachypodium pennatum, will soon spread, but by ameliorating the soil, in 2 years this grass will scarcely be seen (no doubt other grasses beat it out) (Aira cæspitosa will similarly disappear by draining, but there have these is change of condition)

In Wiltshire, S. arvensis has been driven out in some districts by S. alba, the latter having got

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possession of soil by cultivation of mustard for sheep

[James Buckman. 1858. Foreign and native weeds. Gardeners' Chronicle and Agricultural Gazette (2 January): 11.]

Foreign and native weeds.

(The following remarks have been forwarded to Mr. Darwin on the subject to which he refers at page 779. 1857, and are now published with his permission.) In reference to the observation at page 762, 1857, "there is too much reason to believe that foreign seed of an indigenous species is often more prolific than that grown at home?" I would here observe that these remarks were meant more particularly to apply to weeds accompanying cultivation, i. e., agrarian weeds. These long observation and experience have taught me obey the same law as varieties of cultivated plants which become the more prolific and grow better the oftener their change from one soil or situation to another, and I cannot but think that the farmer the better keeps up a vigorous weed growth by those that he sows with seed from various distant places, than from those that he lets seed upon the land. It would be as difficult to trace the origin of many of our agrarian weeds, bot I incline to the belief that many of the weed forms are as much the result of cultivation as the crop itself, for like the crop they are nowhere found truly wild, but are introduced with culture wherever that pertains. If this be so, it is as necessary for the wellbeing of the weed that its seed should be changed as it is for the better growth of a crop, the same seed wearing out in one case as in another. The constant introduction of new varieties of crop plants, as wee as the perpetual change of seed, are so many changes of circumstances by which they were originally produced -and just so is it with the agrarian weeds by which the crop is accompanied. In reference to this I would quote my experiments with Avena fatua. From this I have procured the cultivated types; the A. fatua may thus be viewed as the initiative of A. sativa, but can we view the A. fatua as the primary plant? It is never found except as an agrarian, which I hold as an evidence that it, too, is a derivative. In cultivating all wild plants the first step augments their size on account of the change -seed transported from one district to another continues this change in an augmented form in proportion to the distance, and so all those that are capable of gaining a footing and supporting it do so at an accelerated rate. My own observations in America confirm me in these opinions; there every homestead is full of English weeds, and had I been of Mr. Babington's opinion, I must have looked upon many of them as distinct species from those at home, for not only were many of them more prolific, but they wanted that sturdy character which they possess at home, hence Sinapis nigra on the alluvial banks of the Ohio is as much as 6 feet in height. I find in my notes, written on board an Ohio steamer, "June23: Stuck fast on a sand-bar for the whole day. Went on an island in the evening; good crop of Wheat and Indian Corn. Plants (wild) where European, twice the size of British specimens. Bromus secalinus abundant in the corn" (and I remember the enormous size and height of this Grass). The Chrysanthemum leucanthemum, commonly called Daisy in America, is as much as a yard high in the meadows, or rather where it occurs -an apology therefor. In fact I quite came to the conclusion that even the plants as well as the men became attenuated in the States, and yet with this it may be a question whether both are not more prolific. I have no means of knowing from observation whether imported seed of an aboriginal species in America prevails over the native, but I noticed that in the States agrarian cultivation was affected by the same weeds, with but few exceptions, as our own, and these certainly appeared to me to lose nothing from growth in a new country, but, on the contrary, were larger and more prolific.

As regards the questions about the Sinapis nigra on the farm described, I would beg to state that it was somewhere about seven years since the introduction of this in quantity in some foreign Flax seed. Previously to this it was an occasional plant on the farm (as on what farm is it absent?), pest; this latter has been much got under, not only as a result of better farming, but as I take it fairly driven out of the field before the foreign invader, and in the Flax field, where it was originally sown, it constantly comes up in quantity, while the S. arvensis is here the exception, though time was when it was the law.

"Weed introduced from other land" is constantly driving out the natives. Coltsfoot establishes itself perhaps from seeds from a distance farm or dirty road-side' let it alone or cultivate it as farmers do by ploughing and scattering the divided rhizomes over the field, and the result will soon be that it will gain more or less perfect possession. Leave in a poor meadow clusters of Brachypodium pennatum without ameliorating the soil, and it will soon occupy its greater part. Manure it, and in two years this weed Grass will scarcely be seen. Again, let drainage be defective in part of a meadow for a few years, the whereabouts will be indicated by large bunches of Aira cæspitosa. Remove the cause, and in less than two years most of this weed will die out and be seen on it heels on the sward.

In Wiltshire, to recur to Mustards, the Sinapis arvensis has been driven out in some districts by the Sinapis alba, the latter having got possession of the soil from the cultivation of Mustard for sheep. Lots of instances of the like may be adduced had I time, and indeed so certain is the law of extermination of one form by the introduction of another that I am not sure that the best way to get rid of some more objectionable weeds would not be the cultivation of those less so. J.B.]