Yeah that is a pretty neat oxalis species! Well named too!
Asking "how an oxalis becomes this way" is teleological, you're coming at it from the wrong perspective. It became that way because of environmental pressures on the oxalis population over many thousands of years, this phenotype happened to be the most likely to reproduce successfully.
The question you're probably meaning to ask is more like "how does this unusual physiology make the oxalis better adapted to the Atacaman desert?"
Sorry, you're right. That question is much better and it's what I would want to ask. I was conscious of the word limit of the title that I did not think properly on the question.
Xerophyte plants use the same or very similar strategies to cope with the same environment.
The adaptations here are peculiar for the _Oxalis_ genus, but through convergent evolution the _O. gigantea_ acquired some of the typical tools of the xerophyte plant toolbox: Thickened stem for water retention and nutrient storage, deciduous leaves that can be dropped in the dry season to limit evaporation, extensive root system to harvest and store moisture.
It seems that Oxalis is a bit prone to this sort of thing, [per APweb](http://www.mobot.org/MOBOT/Research/APweb/orders/oxalidalesweb.htm#Oxalidaceae). It has 54 species from arid parts of Chile, and moved into the drier Andean tundra habitat 6-8 times, invaded the hyperarid Atacama and diversified there, while a separate semi succulent geophyte lineage associated with O. tuberosa diversified across the Andes. Meanwhile, separately, over 200 species are diversifying and and becoming succulents and or geophytes across Southern Africa, with 180ish in the cape region, and two separate diversifications into the fynbos and the succulent Karoo.
There is something *up* with Oxalis, something about that genus seems to be primed to readily adapt to arid habitats and diversify there.
Oxalidaceae, the Oxalis family, is a small plant family and the large majority of species are in the Oxalis genus, but there are a small handful of other genuses in Oxalidaceae. Biophytum has some species that are stemmed and the growth habit sort of reminds me of Oxalis gigantea. Averrhoa is another genus and it contains shrubs and small trees, including Averrhoa carambola aka starfruit.
Edit: Not a direct answer to your question, but I made this comment just to provide a little bit more context about this lineage of plants.
Mine is still small but it is not 20cm (pic of the wild below). Mine even exceeds 20cm.
https://preview.redd.it/c0kr8yc15z9d1.jpeg?width=1240&format=pjpg&auto=webp&s=28d84e158774d1e4369000dfb8f1335feb3f806d
Wow that’s really cool. I would think instead of it being a ubiquitous seeding spreader like ours in NA, the harsh conditions caused maximum growth and hardiness of each individual plant. Then again, I’m no botanist and maybe they are everywhere in Atacama as well.
The way Oxalis gigantea has evolved into a shrub form is a cool example of convergent evolution. In the tough desert environment, plants from different families often end up with similar adaptations. You see this shrub-like shape in other desert plants too, since it helps with saving water and getting resources.
What's interesting is that even though Oxalis gigantea stands out in its genus, the Atacama Desert does support other plant life, especially in spots where fog provides moisture or in valleys cutting through the desert. Seeing Oxalis gigantea alongside the well-known Copiapoa cinerea (a cactus species) really shows off the diverse survival strategies plants have developed in this extreme place.
Well yeah, if you really want to follow in Karl’s footsteps. Taxonomy has in fact moved on in the past few centuries. Flower morphology does tend to be conserved though.
Yeah that is a pretty neat oxalis species! Well named too! Asking "how an oxalis becomes this way" is teleological, you're coming at it from the wrong perspective. It became that way because of environmental pressures on the oxalis population over many thousands of years, this phenotype happened to be the most likely to reproduce successfully. The question you're probably meaning to ask is more like "how does this unusual physiology make the oxalis better adapted to the Atacaman desert?"
Sorry, you're right. That question is much better and it's what I would want to ask. I was conscious of the word limit of the title that I did not think properly on the question.
Xerophyte plants use the same or very similar strategies to cope with the same environment. The adaptations here are peculiar for the _Oxalis_ genus, but through convergent evolution the _O. gigantea_ acquired some of the typical tools of the xerophyte plant toolbox: Thickened stem for water retention and nutrient storage, deciduous leaves that can be dropped in the dry season to limit evaporation, extensive root system to harvest and store moisture.
It seems that Oxalis is a bit prone to this sort of thing, [per APweb](http://www.mobot.org/MOBOT/Research/APweb/orders/oxalidalesweb.htm#Oxalidaceae). It has 54 species from arid parts of Chile, and moved into the drier Andean tundra habitat 6-8 times, invaded the hyperarid Atacama and diversified there, while a separate semi succulent geophyte lineage associated with O. tuberosa diversified across the Andes. Meanwhile, separately, over 200 species are diversifying and and becoming succulents and or geophytes across Southern Africa, with 180ish in the cape region, and two separate diversifications into the fynbos and the succulent Karoo. There is something *up* with Oxalis, something about that genus seems to be primed to readily adapt to arid habitats and diversify there.
Oxalidaceae, the Oxalis family, is a small plant family and the large majority of species are in the Oxalis genus, but there are a small handful of other genuses in Oxalidaceae. Biophytum has some species that are stemmed and the growth habit sort of reminds me of Oxalis gigantea. Averrhoa is another genus and it contains shrubs and small trees, including Averrhoa carambola aka starfruit. Edit: Not a direct answer to your question, but I made this comment just to provide a little bit more context about this lineage of plants.
>gigantea >be 20 cm
Mine is still small but it is not 20cm (pic of the wild below). Mine even exceeds 20cm. https://preview.redd.it/c0kr8yc15z9d1.jpeg?width=1240&format=pjpg&auto=webp&s=28d84e158774d1e4369000dfb8f1335feb3f806d
Okay this is more gigantea!
The form Reminds me of the ocotillo
Wow that’s really cool. I would think instead of it being a ubiquitous seeding spreader like ours in NA, the harsh conditions caused maximum growth and hardiness of each individual plant. Then again, I’m no botanist and maybe they are everywhere in Atacama as well.
The way Oxalis gigantea has evolved into a shrub form is a cool example of convergent evolution. In the tough desert environment, plants from different families often end up with similar adaptations. You see this shrub-like shape in other desert plants too, since it helps with saving water and getting resources. What's interesting is that even though Oxalis gigantea stands out in its genus, the Atacama Desert does support other plant life, especially in spots where fog provides moisture or in valleys cutting through the desert. Seeing Oxalis gigantea alongside the well-known Copiapoa cinerea (a cactus species) really shows off the diverse survival strategies plants have developed in this extreme place.
A lot of taxonomy is about the flower and fruit, more than the general form factor of the plant.
Well yeah, if you really want to follow in Karl’s footsteps. Taxonomy has in fact moved on in the past few centuries. Flower morphology does tend to be conserved though.