The seedhead, the panicle, of foxtail plants is a good way to ID the different species, but there is some overlap between giant and green that could lead you to the wrong identification. Much variety within each species exists, biodiversity once again, especially within green foxtail. These differences could be due to genetic polymorphism or somatic polymorphism.
Green Foxtail
Green foxtail seedheads are quite variable within the species:
Robust purple green foxtail:
Green foxtail populations have been selected for millenia as a crop, foxtail millet. They were selected for large and productive panicles, as well as non-shattering (so that seed could be gathered at one time without the seed falling out). Formerly known as Setaria italica (but properly Setaria viridis, subsp. italica):
Variability among regular old Iowa #1 green foxtail:
The panicle below has pronounced branches along the main axis, an unusual variant I found in near Nagoya, Japan. Normally panicle branches are very short, or non-existent. This variant also could be giant foxtail, only molecular analysis can tell for sure:
Below is a mutant panicle, a split seedhead with two branches at the top. This could be a genetic mutant or a developmental error in only this one seedhead:
One of the cutest darn little green foxtails is seen in the pictures below. It is known as green foxtail, variety pachy-stachys. These pictures were taken in a small, isolated Japanese fishing village, just a few miles south of Hagi City, on the main Japanese island of Honshu. It was growing in gravel right at the shore of the Sea of Japan. The soil (?) has to be saturated with saltwater. Maybe this variety could be used to incorporate salt tolerance into foxtail millet:
Yellow or knotroot foxtail panicles:
This panicle is at anthesis, which means in has its sex
organs hanging out for all to see, and making it very likely it will fertilize itself.
Here is a collection of yellow or knotroot foxtail seedheads:
Below you can see another split panicle mutant of yellow or knotroot foxtail:
In India, yellow foxtail populations have been selected over long periods of time for
varieties that have larger panicles, a food crop variety:
Giant foxtail:
Large, and often drooping:
Below is a variety of different colored panicles I took from one field in Japan. The differences could be due to differences in genetics (genetic polymorphism) or to environment (plasticity) or to somatic polymorphism:
Bristly foxtail.
Bristly foxtail seed setae have barbs on them that aid dispersal, they get stuck on
animals passing by. They can hitchhike this way to remote locations, new places to
colonize and infest. The panicles below are all stuck together because of those barbs:
Frequently you can see several foxtail species co-existing together, exploiting a habitat
as a group effort. The species-group:
Which is which?:
Seeds & Seedlings | Leaves, Stems & Roots | Flowers & Seedheads | Foxtail Adaptation
