Chinese Artichoke relatives (Stachys sp. div.)

There exists a few species related to  Chinese Artichoke  (Stachys affinis = S. sieboldiana) which create edible tubers. I grew two of them (three taxons):

Florida Betony (Stachys floridiana) - tubers

Florida betony (Stachys floridana) grows in wild state in southern USA (among others in Florida, Texas, California). This is perennial which creates every year annual tubers. Each tuber gives new plant in next year and dies, and this new plant creates in autumn next annual tubers. The tubers are similar in appearance to ones of  Chinese Artichoke, but they are something longer and have a little different flavor. They have whitish color and characteristic narrowing (look as created from beads). They are edible raw or cooked. This is not sure, but they can contain very small amounts of stachydrine (pyrrolidine alkaloid) (as some other species in genus Stachys) and other biological active components, so can have also a medicinal use (probably anodyne and febrifuge as Chinese Artichoke). It is self-incompatible so to creating the seeds (small nutlets) there are necessary at least 2 various genetically plants (2 clones). It is easy to growing. Likes much of sun and moisture and well drained fertile soils. Tubers can be stored in winter in cool, but frost free place in slightly moist sphagnum moss or sand. They should be planted in direct place in end of April or May (about last frosts date). This is not much frost resistant. In southern lands it can be weedy. This is very little known plant and there is not easy to find its tubers in trading in Europe.

There exists two common wild varieties of Stachys palustris (Marsh Woundwort, Marsh Hedgenettle) in Central Europe: typical variety (var. vulgaris) and field variety (var. segetum). These varieties differ in environmental requirements  and  in  the  morphology  of  underground  parts. The typical  variety  has  often very long whitish tubers with nodes spaced far (several cm) apart and needs wet soil, whereas the field variety forms yellowish tubers with dense, beadlike nodes and is something drought resistant. This last grows the best in  disturbed  habitats,  which  suggests  that  it  may  have  been  grown  in  Central  Europe  in  the  past (as prehistoric vegetable) and then escaped from cultivation. These species (both varieties) is one of the most valuable wild edible plants of Europe. Marsh Woundwort (especially field variety) can be easily cultivated in gardens. It needs medium or heavy soils which good keep moisture and much of sunlight. It is full frost hardy in zone 5/6. The tubers are slightly bitter in flavor. They taste the best when fried. It can be propagated by tubers or seeds (these last probably do not need any pre-treatment to germinating, but should be sown surface or shallowly).

The comparison of tubers appearance of two varieties of Stachys palustris (Marsh Woundwort) - on the left - field variety (var. segetum), on the right - typical variety (var. vulgaris)

Stachys palustris (Marsh Woundwort, Marsh Hedgenettle) - typical variety (var. vulgaris):

The tubers of this variety are usually white and with far disctance between nodes

.. and can be very large

Young shoots

The plant in flowers

 Stachys palustris (Marsh Woundwort, Marsh Hedgenettle) - field variety (var. segetum):

The tubers of field variety are usually yellowish and with densely distributed nodes

There are a few other rare tuberous Stachys species in subtropical and temperate areas of the world. If you have the tubers or seeds any of them please write to me. 
 There is a link to my article about 2 varieties of Stachys palustris (in Polish language, with English abstract and summary and with photos):
http://maxbot.botany.pl/cgi-bin/pubs/data/article_pdf?id=4209