Reservoir edge

As usual we were in the Iberian peninsula during the least flowery time of the year: September-October, at the end of a long, arid summer. 

We went for a swim; in the shallows it was like a bath. I had never seen the reservoir so low. 

But here, along the sandy shore exposed by the shrinking water, there were quite a few flowering plants, so after my swim I took some photos. 

The plant with the white flowers is Corrigiola litoralis, known in British floras as Strapwort. (It is native to the British Isles but incredibly rare, only now in S. Devon.) 

A thousand miles to the south, it was the commonest plant along this shoreline. At first glance I supposed it was a member of the cabbage family, but then I saw that the flowers had five petals not four. Corrigiola is actually in the campion family Caryophyllaceae. 

Rough Cocklebur (Xanthium strumarium). A much-naturalized plant; it's uncertain whether it originated in America or in Asia/S. Europe. 

Once I noticed them, these were the plants that intrigued me most. They were tiny (compare the size with Strapwort in the photo below); they were also in full flower. I had no idea what they were, but Google Lens went for Cyperus and I think that's probably right, though I wouldn't be too shocked if it turned out to be something like Carex bohemica. The problem is that these plants are usually photographed (and drawn) at a later stage in their development, when the stems have elongated and the flowers have morphed into the larger and more distinctive fruits. 

Specifically, the image-matching app went for Cyperus squarrosus, the Bearded Flatsedge of America. But in Europe this species is only naturalized in a few places in Italy. 

I really needed to consult Filip Verloove, whose conspectus of Cyperus, a very difficult genus, is well worth tussling with.

https://www.researchgate.net/publication/269705349_A_conspectus_of_Cyperus_sl_Cyperaceae_in_Europe_incl_Azores_Madeira_and_Canary_Islands_with_emphasis_on_non-native_naturalized_species

Here's a plant I feel a bit more confident about. It's either Bidens tripartita (Trifid Bur-marigold) or something extremely like it. Locally common in the southern British Isles; I've seen it in Frome, too.

A little grass plant.

Purple Sand Spurrey (Spergularia rubra), I think. But if it is, the basal rosette in the centre is actually a different plant, perhaps Buck's-horn Plantain (Plantago coronopus).

I'm sorry about the dull light in this photo. When we made our second visit to the reservoir, it was still very hot but the sky was no longer blue. We had a week of Saharan dust: the sky pale grey and the setting sun a weird white, like the moon. 

By the way, I suppose everyone except me knew this, but if you click on a photo in this blog you get a much sharper rendition (especially on your phone).