The following are three more species I'd like to identify for my collection. All of them were taken in my home city, Montevideo. The red flowered one appears to be a Rodophiala bifida but I'm not so sure.
#2 looks like Gladiolus tristis, a South African... I think #3 is one of the Chenopodiums known as Blitum in the past, but you'll have to look in a local flora for the species name.
Thank you all for your contribution! I'll try to consult local bibliography. As far as I've read Chenopodium ambrosioides might be the name of the third specimen.