Benny's "key" to the
Yucca filamentosa & Yucca flaccida complex.

As you may know is the eastern acaulescent species of Yucca a mess, and my "key" is the way I think this mess could be solved. You might think the following is a blurb, but I have a point by the "weird" way of writing, and I hope you get it?

If the Yuccas in Virginia and on Roanoke Island is the form concava then this would be the "type" form and rejected in favor of Yucca filamentosa. The plant chosen by Fernald has leaves like what I would call "concava", but what about the forms with narrower leaves and less spathulate leaves, this is what today is called Yucca filamentosa, but they can't have this name if this name is for for the form in Virginia and Roanoke Island = the "concava" form! so the narrower leafed form may need a new name?

Question; does the narrow leafed form have branches on the inflorescens like Yucca flaccida? If it has the narrow leafed form could be a hybrid between Yucca filamentosa (Virginia and Roanoke Island form) and Yucca flaccida?

I don't have Haworth's description of Yucca concava, but if his description fit's the Virginia and Roanoke Island form this name should be synonymous for Yucca filamentosa.

If the above questions is as I suspect, the following "key" is my opinion for the Yucca filamentosa & Yucca flaccida complex. Note! not all combinations are "legal" but I think you get my idea of the picture:

Yucca filamentosa ssp. filamentosa
From Coastal area from southern Maryland to Virginia, North carolina, South Carolina and just into Northern Florida.
Short, wide and quite spathulate leaves, glabrous flower stalk, only few short branches on the inflorescens, glossy seeds.
(This form is better known as Yucca filamentosa ssp. concava!)

Yucca filamentosa x flaccida
Also from coastal area in North Carolina.
Narrower leafed form with stiff leaves and curly fibers, glabrous or pubescent flower stalk, more and longer branches on the inflorescens, Fruit: The young capsule is apple-green, and has a rounded (convex) back, 50 - 60 mm long, brown when ripe, seeds glossy.
(This is the form that is known as Yucca filamentosa!)

Yucca filamentosa ssp. flaccida
From the mountains and hills in the Blue Ridge and other inland locations.
Floppy leafed form, very pubescent flower stalk, many and long branches on the inflorescens, broad and abruptly short-acuminate petals. The young fruit it has an angular back, 50 to 70 mm long. Seeds: black, rather dull. large 7-8 x 8-10 mm. Seeds dull.
(This is the form that is known as Yucca flaccida!)

Yucca filamentosa ssp. flaccida forma glaucescens
Floppy, wide bluish leafed form, from the mountains and hills. Tall pubescent flower stalk, many and long branches on the inflorescens, dull seeds

Yucca filamentosa ssp. smalliana
Inland (not coastal!), southern South Carolina south to central Florida
Narrow and floppy leafed form, very pubescent flower stalk, many short or long branches on the inflorescens, smaller flowers. The young capsule is purple to dark green, and has a rounded (convex) back, 50 - 60 mm long, brown when ripe, I don't know the seeds from this one yet!
This one could be a hybrid of Yucca flaccida x Yucca freemanii or Yucca flaccida x Yucca arkansana!

The above is only made mostly by the look of the leaves and the flower stalk.

The distribution of the "eastern" Yuccas may not give a "natural" picture. While Yucca filamentosa and Yucca flaccida (which it is often confused with) is often naturalized in areas where it didn't original grow. This naturalization is probably already started before Columbus did find the new world (*1), while native americans has probably grow Yuccas near their homes, so they have had easy access to the leaves for fibers and to the roots for soap.

In a few years, when all the plants from seeds, that I have ordered from Fritz Hochstätter has flowered, will I get a better "picture" of this "mess"

I hope you aren't more confused than you were before?

If you live in the natural area of the eastern Yucca's would I be very happy if you could send me seed pods, seeds, photos of plants in habitat.

Send to:

Benny Moeller Jensen
Aalborgvej 305, Haestrup
DK-9800 Hjoerring

or send an email to

Actually was it the Norwegian "Leif the Happy" son of "Erik the Red" that first did find the new world in the year of 1000, the land was at that time known by the Scandinavian vikings as wineland.

Back to Yucca flaccida:
Back to Yucca filamentosa:
Back to Yucca smalliana:
Back to list with Yucca species:

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