Wednesday, May 15, 2013

An introduced invasive - in 1710

Patrick and I have gone through some of John Lawson's specimens - so far we've done determinations on his specimens in H.S. 158 and H.S. 145. These are intriguing because they were collected in 1710 or earlier (couldn't have been later, because Lawson was killed by Indians in 1711 - more on that in a bit). That was long before major European settlement in the Carolinas, more than a decade earlier than Mark Catesby. Lawson wrote a really great book about his adventures, A New Voyage to Carolina, which describes his fun with native Americans after most of them had died from smallpox but before they disappeared as a significant social force in the area. (Many thanks to UNC for digitizing this book!)

Anyway, Lawson was kicking around the Carolinas EARLY. The Lords Proprietors didn't get going with the Province of Carolina until 1663. Charleston, SC was founded in 1670. (This would be a great time to review my Restoration history - you known, when Charles II took the monarchy back in the wake of Oliver Cromwell's death.) Lawson set out for the Carolinas as an explorer, mainly because he heard that Carolina was the best place to go, and spent the next decade traveling around the countryside. His writing displays enthusiasm for his surroundings, keen observation of both natural history and human interactions, and a good sense of humor at said interactions. Also, his descriptions of animals combine observations on their physique and behavior with culinary notes. His book was a bestseller in Europe and persuaded many would-be settlers to follow Lawson into the wilds of Carolina.

Because Carolina was still wild when Lawson was there. There were some settlements, and some farms, but much of his food on his journey came from native Americans who were hunting and gathering wild foods. Not many Europeans had yet arrived in this area.

So imagine my surprise to find a specimen of Rumex crispus, curly dock, in his collection! (It's on H.S. 145 f. 62.) He (or someone) even wrote a note on it - "Wild dock a sorrell, Trout River June 20th 1710, vid with Leed[?]"(Lawson's handwriting is a bit difficult for me to decipher. "Vid" means "saw", and I think he is saying that he saw this plant with a man named Leed, or perhaps Lord.) The remark about "sorrell" is correct, as all the members of the genus Rumex are commonly called docks or sorrels.

This plant is native to Eurasia. It's currently present in every state in the U.S., and most of the world too. North Carolina now considers it one of the most troublesome invasive weeds in the state. The seeds get into agricultural seeds and they stick to clothing. So how did the darn thing get to the Trout River by 1710? Did some Englishman go walking in the countryside and then board a ship without washing his trousers? Did someone carefully save some seeds to plant in the New World, as a healthful taste of home?

In any case, that sure was fast. People move, and plants go with.

Catesby collected a bunch of introduced plants 13 years after Lawson. In a couple of weeks I'm going to the Sloane to photograph more plants collected between 1700 and 1710. We shall see how much of old Europe had managed to establish itself in North America by that point.

Oh, Lawson's death? Well, in his own book, Lawson describes a method of torture used by Indians in which they would stick a victim full of pine splinters and then set him on fire, to dance to their delight. Lawson was captured by the Tuscorora Indians in 1711 and apparently put to death, though no one knows exactly how this occurred. Lawson's friend Christopher Gale claimed that he died according to the pattern he had himself described. Qui sait?

Wednesday, May 8, 2013

Animals in the Herbarium

If you've ever been snorkling or scuba diving in the Caribbean, you will have noticed waving fields of things that look for all the world like plants. They grow out of the sandy or coral bottom, they are branched, and they sway gracefully in the current.

Plants they are not, though. You are looking at animals called gorgonians, also known as sea fans or sea whips. They're related to coral. (Sorry for citing to Wikipedia. Wikipedia is a good reference!)

What makes them animals and not plants? Among other things, they can't make their own food. They have to catch plankton and eat that. (Actually, lots of gorgonians do have symbiotic relationships with photosynthetic algae that produce some food for them, but in no sense are gorgonians plants.)

When Mark Catesby visited the Bahamas, he had no way of knowing that the sea fans he saw were not plants. They sure look plant-like! So he collected a gorgonian, and sent it off to London with his other herbarium specimens. That is why there are animals in his herbarium at Oxford.

Introduced Plants - circa 1723

Introduced species are a big deal in ecology. Species move around all the time, of course, but natural evolution tends to be slow and gradual. Plant species that evolve in a place are adapted to the local environment, and while the "balance of nature" is something of a myth, slow evolution makes for more stability. Introduced species appear abruptly, without slowly accommodating to the denizens already in place. Introductions may run roughshod over the local inhabitants because they aren't vulnerable to the general threats - these introduced species can become invasive. Humans have introduced species all over the world, both deliberately and accidentally. The process of introduction really took off in the 17th and 18th centuries, as Europeans sailed all over the globe and carried plant materials back with them.

But how can you tell if a species is introduced? How do you know when an introduction occurred?

Charleston, South Carolina, was founded in 1670. By 1690 it had become one of the five largest cities in the colonies. It was a major port and a hub of trade between the American colonies and the Atlantic. Ships arrived in Charleston from many locations. Ships arriving from Africa brought slaves. Ships from England and the rest of Europe brought settlers and manufactured goods. Ships from the Caribbean and South America would also have stopped in at Charleston.

Mark Catesby visited Carolina in the period between creation of the crown colony of Carolina in 1719 and the separation of South Carolina from North Carolina in 1729. He arrived fifty years after Charleston was established, and after decades of transit and trade had moved around myriad plants and animals, but BEFORE extensive European settlement of the area. The plants he collected thus contain a snapshot of the botany of the region early in the colonization process. Most of his collections are native species, but some introductions had already arrived.

The following species in Catesby's collections are all considered to be introduced or possibly introduced to the Carolinas (per Alan Weakley):
Dysphania ambrosioides (Linnaeus) Mosyakin & Clemants        00087426R
Gaillardia pulchella Fougeroux var. pulchella        00087294U, Sher-1957
Helianthus debilis Nuttall    Sher-1944-2
Stokesia laevis (Hill) Greene            Sher-1641
Tarenaya hassleriana (Chodat) H.H. Iltis = Cleome hassleriana Chodat            00087297X
Ipomoea coccinea L.  H.S. 232 f.61
Jacquemontia tamnifolia (Linnaeus) Grisebach    00087560Q, Sher-0359
Momordica charantia L.        Sher-2195
Croton glandulosus Linnaeus var. septentrionalis Müller of Aargau      Sher-2069
Indigofera tinctoria L.           H.S. 232 f.106
Mimosa quadrivalvis L.         H.S. 232 f.107
Senna occidentalis (L.) Link             H.S. 212 f.1, H.S. 212 f.81
Nepeta cataria L.       00087449W
Prunella vulgaris L.   00087454S
Modiola caroliniana (L.) G. Don       00087276U, Hort-004-004
Sida rhombifolia L.    00095695Y, H.S. 212 f.51, H.S. 212 f.50
Digitaria sanguinalis (L.) Scopoli     Sher-0125
Echinochloa crusgalli (L.) Palisot de Beauvois       00087523P
Eleusine indica (L.) Gaertn. H.S. 212 f.85, 00087562S
Eragrostis cilianensis (Allioni) Vignolo ex Janchen           00087570R
Hackelochloa granularis (L.) Kuntze           00087527T

NB: H.S. references are in the Sloane Herbarium. Sher-#### and 00##### references are in the herbaria at Oxford University.

Some introductions were likely deliberate. Nepeta cataria L. (00087449W) is catnip, a common garden herb native to Eurasia. It is easy to imagine a colonist bringing seeds from Europe to start an herb garden in Carolina.   

Tarenaya hassleriana (Chodat) H.H. Iltis (syn. Cleome hassleriana Chodat, 00087297X), is the spiderflower or spider plant commonly grown as an ornamental. The note on the bottom of the herbarium sheet reads “Sent from South Carolina by Mr. Mark Catesby.” This species is native to South America. The Flora of North America describes it thus: “Tarenaya hassleriana is native to Argentina, Brazil, and Paraguay. It is often cultivated and has sometimes escaped and naturalized. In cultivation and various floras, it has long been treated under the name Cleome spinosa…..”.  

Cleome was apparently a favorite of Thomas Jefferson, who grew it in his gardens at Monticello; construction on the house began in 1768 and work on house and gardens continued for several decades. The plant is an aggressive self-seeder.
So did Catesby really find this plant in South Carolina? It is plausible; certainly there had been traffic between the cleome’s native range and the Carolinas for decades by the time he visited.
The presence of particular taxa in Catesby’s collections may or may not be significant. It is impossible to know where he collected his specimens, or the conditions in which they were growing. He certainly could have gathered plants from cultivated gardens. But it is also possible that some of the introduced plants he collected had already escaped from cultivation. It is also true that we do not know for certain that the plants in the herbaria were collected in Carolina; even the ones with handwritten notes claiming South Carolina provenance might have in fact been collected elsewhere. What we can say, however, is that the presence of these taxa in Catesby’s collections strongly suggests that these plants were growing in South Carolina or possibly Georgia in the 1720s.