I don't think I have mentioned Sprekelia until recently when my Sprekelia howardii set some seed. Sprekelia is a very small genus of only two species, both of which are found in Mexico. The common name is Aztec Lily, although they are not actually lilies.
Sprekelia formosissima is commonly available, and is sometimes used as a garden plant in the southern states of the USA. It is found from Guerrero and Chiapas, though Guatemala and Honduras.
Sprekelia howardii is quite rare. It was found in southern Mexico as recently as the year 2000, and is not generally available. It has the same deep crimson flowers, but a much more elegant form, with petals that are like satin ribbons. My bulbs do not bloom every year and are very slowly increasing.
Both species should be grown in a fast draining mix. They have been prone to fungal disease, so I grow them in a mix that mostly is horticultural pumice with a little organic material.
This mix, and repotting regularly, has been more effective in controlling stagonospora than using fungicides. Neither species is very hardy, so growing them outside in the garden is only possible in the mildest climates.
The seeds from Sprekelia howardii have been sown, so hopefully I will have some available in the future.