Wildflowers: Weeds in Northwestern Argentina

The rainfall in Salta Province, Argentina, ranges from nearly 30" a year to 17 or less, almost all during the hot summer months. The countryside, though beautiful, can be rather inhospitable to plants.

Streams run through it, making marshes

People live in the valleys and have turned the steams and rivers into irrigation water so they grow rich crops, especially wine grapes.

I walked a path through the vegetable garden of the Vinas Cafayate Wine Resort in Cafayate at the southern end of Salta Province.

There were wonderful weeds, flowering because it was spring (October). Mostly they were members of genera I knew from western North America, but species new to me. That is, South American wildflowers. How did they get to the green valley between the stark dry hills? Probably each has an interesting tale.

Argemone, cardo santo

This is Argemone, prickly poppy, poppy family, Papaveraceae (North American species link). This is likely Argemone subfusiformis, an annual native to Argentina and Chile and far the most widespread of three native Argentine species of Argemone. Its Spanish name cardo santo, means blessed thistle. The name cardo santo is used for various Argemone species across the Americas, but is also the name given thistles of medicinal value (wavy-leaf thistle, Cirsium undulatum sunflower family, Asteraceae in Mexico blog) and for the blessed thistle of Europe (Cnicus benedictus in the sunflower family Asteraceae pictures). Species of Argemone are used in traditional medicine all across the Americas.  Argemone subfusiformis, cardo santo, is a handsome plant, with big white to yellow flowers and spiny leaves that often have white lines down the center. It is widely grown as an ornamental. Here's a close-up looking into the flower:

Argemone, probably subfusiformis, cardo santo

Clematis (genus Clematis, buttercup family Ranunculaceae) was quite common growing on roadsides in Salta Province, but this one was sprawled on the ground in the path beside the crop rows. There are about 300 species of Clematis worldwide and many are grown as ornamentals, since they are pretty vines with flowers from white to deep purple. I can't find much information on South American species of clematis. This one looks like some of the South American natives but is certainly pretty enough have escaped from a garden.

clematis 

Among the onions: a morning glory!

Morning glories, genus Ipomoea, are native to the American tropics, with many very similar-looking species (vines with blue-purple trumpet-like flowers, morning glory family, Convolvulaceae). Many are natural weeds: short-lived plants of disturbed areas, growing quickly, rapidly scattering their seeds. Of course they have moved into crop fields. A very cheerful flower that will have wilted by afternoon.

Below is an evening primrose, probably an Oenothera species (evening primrose family, Onagraceae). The evening primroses (unrelated to roses or primroses link) are an American genus with 145 or more species, distributed on both continents. This plant does not match any of the Argentine or Chilean species that I can find to compare so I can't suggest which species it is. And when I look in floras for southern Mexico, I see it could be a closely related genus and a suncup (genus Camissonia) not an evening primrose.

And then I saw a wonderful wild four o'clock (Mirabilis, four o'clock family, Nyctaginaceae). An American group, four o'clocks were a hit when first brought to Europe. Gerard, writing about 1600, called what is now our garden four o'clock, Mirabilis jalapa, "marvel of Peru." There are native species of Mirabilis all over the Americas. The weedy species that shows up in my yard has pale flowers, not like this beauty:

There were other plants in flower, a wild tobacco (Nicotiana), a poppy mallow (Sphaeralcea), goosefoot (Chenopodium, special because quinoa is a Chenopodium species native to northwest Argentina/northern Chile)...lots of things to stop and notice.

the path beside the gardens

I usually think of native plants in regard to their North American distribution. Recognizing plants related to plants I know when I'm half way down South America--that was a serious reminder that political borders are irrelevant to plants. We compile a Flora of North America North of Mexico (link) but plant distributions lap into Mexico...and Guatemala, and southward. Many plant genera leap the American tropics, to diversify in subtropical and temperate climates in North America and South America. The November 2017 issue of the American Journal of Botany featured those plants, amphitropical they call them. Some patterns of plant diversity can be understood only looking at North America but others, rather a lot of others as indicated in my stroll along the Cafayate garden, need to include South America.

Flowering wild tobacco (Nicotiana) ?

Comments and corrections welcome

References
American Journal of Botany. Patterns and processes of American amphitropical disjunctions
November 2017. link
Haene, E. 2007. 100 Flores Argentinas. Editorial Albatros, Buenos Aires.
Moore, M. 1990. Los Remedios. Traditional Herbal Remedies of the Southwest. Red Crane Books, Santa Fe, New Mexico.
Online pictures of the plants named.
Rebman, J. P. and N. C. Roberts. 2012. Baja California Plant Field Guide. 3rd ed. San Diego Natural History Museum, San Diego.

Kathy Keeler, A Wandering Botanist

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Related blogs:
Flowers of the Atacama Desert link

A Glipse of Northern Chile link

A Glimpse of Northwestern Argentina link