Native Agave Species, Probably Not Native and Perhaps Not Even Species

23 Sep

Agave sisalana

Agave decipiens

Agave neglecta

John and George this week indulged their multi-week fixation on the Savannas Preserve State Park and neighboring scrublands.  Yesterday we were working on the railroad all the live-long day.  Railroad tracks are interesting botanically, because the rights-of-way have been there a long time as unintended plant refuges, and because choo-choos spread species.   The floral beauty this week is stunning with yellows coming from Goldenrods, Crotalarias (not necessarily native), and weird little Neptunia.  Butterfly Pea (Centrosema virginiana) was so abundant and so gorgeously blue-violet to surpass the average flower garden.  Giant Foxtail Grass (Setaria magna) was swaying in the breeze with the bristly inflorescence actually the size of a fox’s tail.

But the great encounters were all three “important” Agave species growing untended in Florida.  Agaves are about as fascinating as they are beautiful, with a complex history in human affairs.

Agave sisalana (by JB)

First on the list is an abundant but definitely non-native Agave.  Florida once was a hotbed of research on fiber plants, one of them being Agave sisalana, the source of commercial sisal fibers, as in ropes, doormats, and similar rough-scratchy commodities.  Agave sisalana is still with us in scrubby places.  It is the only common Agave in natural areas having no (or few, small, and irregular) prickles along the margins of mature leaves. Recognize this species from the distance by its straight narrow leaves with comparatively parallel margins.  Agave sisalana is a Florida Exotic Pest Plant Council Category II invasive exotic, which raises a question, how can a seedless species invade?

That’s easy:  Agave sisalana, like most agaves, forms “bulbils” in its maturing inflorescence. Bulbils are baby clones of the parent plant; they represent vegetative reproduction and do not grow from sprouting seeds. Neither fruits nor seeds are known in A. sisalana.  The bulbils are tougher than nails, and can float and can last forever unrooted; they are the “perfect” propagules.  Bulbils are useful for humans wanting to cultivate agaves, which has been goin’ on a long time.

Agave remains decorate human excrement on the order of 6000 years old in caves.    CLICK and


(Do you think somebody will be examining our leavings 6000 years from now?)

Agave sap burns human flesh (believe me!) to the point of being dangerous to the eyes, yet pre-Europeans served agaves in the kitchen, wrapping food in the waxy cuticle, chewing quids made of the leaves, eating the plant flesh, and sipping the sap in beverages.  The last-mentioned practice grew into a Mexican industry.  Just ask Jose Cuervo.

Agave fibers are beautiful strong, easily extracted by rotting the flesh off of the leaf, and just plain nice.   We’re talking about ancient cordage, hammocks, and fishing gear.

Prehistoric sandals probably made at least in part of Agave fibers (from the second link provided above)

So now a few strands of our story come together.   Agaves originated almost certainly in or near Mexico and Texas where human civilization is ancient.  The plants were valuable for foods, drinks, and fibers.   They are easy to store, move, and plant.  This all ties into a big Agave fact.  This is important, so listen carefully:  multiple named “species” of Agaves are in fact ancient cultivars and hybrids, created and moved around by the hand of people and their canoes.  This helps explain the sterility, wacky variation patterns, mixed chromosome numbers, and distributions of some “species,” including the Florida “natives.”

Not proven, but personally I am convinced that that’s the story behind the Agaves distributed among the Caribbean Islands.   Ancient Caribbean-dwellers were expert mariners and fisher-persons.

And all this begs a huge inadequately investigated question—a question hobbled by a reluctance among traditional taxonomic botanists to take pre-Columbian civilization into account in assessing modern plant distributions.  The question is: how did agaves come to Florida?  Possibility 1:  The Tex-Mex scrub flora around the Gulf was more or less contiguous with present-day Florida scrub.  There are western carry-overs from those times still with us in Florida.  Possibility 2:  Maybe the indestructible bulbils floated across the Gulf or Caribbean Sea, or maybe seeds fluttered here on the salty breezes.  Possibility 3:  If humans were growing agaves on Caribbean Islands, couldn’t the canoes have stopped by for a Florida vacation?   Or could humans have carried bulbils around the Gulf from Mexico?

Agave decipiens (by JB)

The level of involvement of Florida in pre-Columbian Caribbean commerce is not known.  Those who wonder how Papayas got here ponder this.  Here is an unstudied silly notion:  our Florida Agave decipiens resembles the Caribbean Agave karatto.  In Flora of North America, botanists James L. Reveal and Wendy Hodgson suspected the history of Agave decipiens to be rooted in human activity:  “Agave decipiens might have been introduced from Latin America by Native Americans; it is not otherwise known from the wild. The proliferation of chromosome numbers suggests prolonged human propagation and a probable hybrid origin.”

Agave decipiens is a large Florida endemic recognized by the even and well-developed (although of variable length) bristles fully along the leaf margins.  The leaves are almost-straight, with little twists and shape irregularities; the margins not as parallel as in Agave sisalana, which differs further by having no or very few marginal prickles.  There can sometimes be a short “trunk” at the base.  The species is beautiful and in cultivation, although a glance at Google Images reveals material cultivated under this name to be a little “dubiously identified” at times.

Even prettier is our likewise endemic Agave neglecta.   The leaves are broader (> 15 cm) than those of A. decipiens and of A. sisalana, and far more curved.   The fine mini-prickles are restricted to the lower half of the leaf margin,  As with Agave sisalana, fruits are reportedly not produced.   (However, there are specimens with fruits bearing this ID in Florida herbaria—see discussion below.  Sterile and fertile plants are possible—this occurs in the similar A. karatto, and could be either most likely cytological variation, or sometimes merely a question of pollination.)  The taxonomic King of Agaves, Howard Scott Gentry, as reported in Flora of North America, felt that Agave neglecta resembles Agave weberi cultivated for its fibers.  Reveal and Hodgson in FNA suggested, “The plant [A. neglecta] may well be a cultivar of A. sisalana or A. kewensis and represent an ancient introduction from Mexico.”  (We do not see the Agave sisalana similarity except for the missing fruits.)  Most agaves are pollinated by bats, which begs another question.  Do Florida agaves achieve pollination?  If pollinated, would the fruitless Agaves make fruits and seeds?  I don’t know, probably not, but worth a try with a step-ladder, paint-brush, and a few baggies.

Agave neglecta (by JB)


Posted by on September 23, 2012 in Agave


Tags: , , ,

19 responses to “Native Agave Species, Probably Not Native and Perhaps Not Even Species

  1. Mary Hart

    September 24, 2012 at 3:52 am

    Very educational to follow archaeological links in the article.

  2. George Rogers

    September 24, 2012 at 8:12 am

    Mary, When looking at Agave long ago, I wanted to visit St. Lucia for a looksee but never managed to. Agaves get a lot of “light” research. What the world needs is for somebody with a broad view and high tech skills (and tons of money) to devote an entire career to them…

  3. Steve

    September 24, 2012 at 12:13 pm

    There is no doubt that humans move plants around. That Neptunia from up your areas was likely brought inadvertently from Dade county along those railroad lines, in fact many populations of tropicals extending in your areas moved around that way, and likely temperate stuff further south.
    I wasn’t aware that Agave sisalana didn’t have seeds, and I am surprised by that. This species has a marvelous history in south Florida, as it was introduced by botanist Dr. Henry Perrine in the 1830’s. He introduced it to south Florida with the intent on bolstering the U.S. production of fiber for rope making sorely needed by our Navy, and he was provided with a 35 square mile land grant to do just this. Perrine lived out on Indian Key (the original county seat for newly formed Dade County) in the FL Keys, and was killed during the second Seminole War before he had a chance to achieve his goal, however he did place a bunch of plants out on Cape Sable as well as in the Florida Keys. He had been killed during the “Indian Key Massacre” by the last remnant of Calusa or Spanish Indians, who many moons ago likely first brought Agaves to Florida, Ironic huh?
    A. neglecta does produce seed however (see: and I would have thought A. decipiens too, but I cannot recall or verify. Many nursery growers do collect seed from some species of cultivated Agaves down here.
    Many traditionally bat pollinated species are pollinated by large sphinx moths (e.g. Black Calabash, Amphitecna latifolia), I suspect they visit Agave flowers too.

    • George Rogers

      September 24, 2012 at 12:37 pm

      I do see those specimen(s) you mentioned with fruits/seeds. As Agaves are so often mis-ID’ed I do wish the colelctors had included the leaf margins so we could verify the determinations. (What is often done with Agaves is to trim the margins off the leaves and press, dry, and mount those.) I am familiar with that clump in Loggerhead Park, whcih (without really a serious examination) always took blithely to be A. decipiens. Unfortunately I think those plants are now gone or much reduced. Will look next time I’m there. Thanks for pointing out those specimens. I’ll re-edit the blog to reflect them.

  4. George Rogers

    September 24, 2012 at 12:32 pm

    Thank you Steve. If I ever have time, which won’t happen, I’d like to look into the relationship of A. decipiens with A. karatto, but to be doen right that really requires a comprehensive study of the entire genus. I’ll look at the A. neglecta specimen you mentioned and change the text as needed.

  5. Steve

    September 24, 2012 at 10:28 pm

    No sweat, if you look again at that A. neglecta specimen, there are three sheets, and sheet 2 of 3 has the margins. that is actually my specimen I collected over ten years ago, and misidentified it as A. sisalana. How embarrassing, I should of gotten that one right. 🙂
    I’ve got A. decipiens in the yard, and will look for polllnators & seed set when if flowers in a bizillion years.

  6. George Rogers

    September 25, 2012 at 8:22 am

    10-4. I should have found the other two sheets. Haste makes waste.

  7. John

    September 29, 2012 at 2:21 pm

    Definitely didn’t know there were so many different species of Agave. As someone getting into spirits, I was always curious about the Agave plant in general. This is some pretty interesting info. Thanks.

    • George Rogers

      September 29, 2012 at 8:07 pm

      John, I’ll say! What there is to know about Agaves is infinite. They have some of the oldest and most profound roots in New World human history of any plants I can thing of, except maybe Maize. For me, Agaves represent the depth, breadth, and general hugeness of pre-European human culture in the New World. Sometimes I feel like I can hardly get my mind around that. A powerful reminder that it didn’t all start in 1492. DNA technology is going to “write the book” on Agave history one of these decades.

  8. Kimberly

    September 29, 2012 at 5:38 pm

    Fantastic blog! I’m following. Bravo!

    • George Rogers

      September 29, 2012 at 8:03 pm

      Thanks Kimberly, and delighted to have your participation! -George

  9. SmallHouseBigGarden

    December 31, 2012 at 11:15 am

    is A. sisilana sold anywhere?

  10. George Rogers

    December 31, 2012 at 11:22 am

    Not that I am aware of (but thre’s much I’m not aware of). Would be easy to obtain though, cuz the inflorescence as it goes into declines makes about a million bulbils. They drop all around the parent plant and can be potted up.

    • SmallHouseBigGarden

      August 3, 2013 at 4:29 pm

      I just revisited this article, as I’m contemplating buying some type of agave, and naturally want one that will thrive here in Vero.
      I was recently up in Daytona and there seem to be agaves EVERYWHERE, though none I could actually steal a bulbil from. I so rarely see them here in town but am keeping an eye out!
      I have recently found an online source called “the Desert Northwest” the blog owner is much like yourself: very horticulturally aware with many articles and links to interesting sites with archeological and anthropology involved. If you haven’t looked at his site yet, I highly recommend starting with his domestic agave article:
      Thanks again for such an educational blog!

      • George Rogers

        August 3, 2013 at 4:59 pm

        Thanks, and I wish I knew where in Vero to nab a legitimate bulbil. Well, yea, I do have one idea—McKee Gardens—they used to (and probably still) have some nice agaves at the entrance. If there are bulbils no doubt they’d offer some…or at least they could steer you the best agaves for Vero.. Will take a look at the blog you suggested right now—thanks again, George

      • SmallHouseBigGarden

        August 4, 2013 at 9:14 am

        mckee! I’ve been there many a time but not during “bulbil” season. When I get back from Key West (the end of the week) I will get over there. I hope to bring back some cuttings from Key West, too…whatever strikes me and is easy to get without feeling like I;m stealing!

  11. George Rogers

    August 4, 2013 at 12:33 pm

    There are some amazing beautiful native agaves in the Antilles, and I’d love to know if any grow on Key West.
    Fine line on “harmless bulbil removal” and stealing-trespassing isn’t it!? Something I’ve learned from a lifetime of weird botanical shenanigans is that most people love it when you show an interest in a plant in their garden, and are free and easy about permissions for reasonable snippets. Years ago I saw a plant (an apparently wild-growing uncultivated pecan) that interested me in a rural yard in Missouri. Really rural. I mean movie-setting. I trespassed intending to snatch a few ripe nuts and skedaddle, but a scary unshaved guy clearly not fully sober came running out of the shack with a shotgun in hand and a stand-yer-ground attitude. Yikes! But upon explaining my mission while looking into the business end of the shotgun, the man did an attitudinal 180. He was interested in the wild pecan tree too and had wondered about it, even planted its seeds. He invited me in to meet his wife and dog, and we all spent most of the afternoon finishing off a bottle of whisky most congenially.

  12. Wendy Hodgson

    April 7, 2014 at 3:50 pm

    Hi George, love this website and glad you are continuing with your interest regarding preColumbian agaves. Are you studying in depth the Florida agaves? Andrew Salywon and I would like to visit and try to get a tip of a toenail hold of what might be going on there. Here in Arizona the story continues to become more complex, with basic questions far from being answered, although Andrew’s (and Kathy Parker’s) molecular work helps considerably (and thankfully, so far supports most of my ideas and gut feelings). All the best.

    • George Rogers

      April 7, 2014 at 3:59 pm

      Hi Wendy. Wow! What a wonderful surprise to see you here! Unfortunately my real job keeps me from digging into serious agave work. What a pity. As you know, you could not have a more fascinating plant group…BUT, if you ever wish to visit S FL for some agave material/data, I do know where to see the “natives” in this neck of the woods and would be thrilled to help you in any fashion possible, including sending material if ever that would be useful. My e-mail is


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