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Indian Laurel Fig Has Two-Step Delivery

03 Sep

Ficus microcarpa

Moraceae


Every South Florida resident knows Ficus microcarpa as the ‘Green Island’ Ficus that has become a preeminent hedge and space filler selections in local landscaping.   It is bugproof and idiotproof, which is why I have it in front of my house.    Asking nothing in return, it just stays flawless green, and grows. 

When not serving as a hedge, “natural” Ficus microcarpa can grow into a giant multitrunked “banyan.”   Or to pivot to the small extreme, it is a favorite tropical bonsai species.   I have a couple of those on the back patio.   Or… it can be “the other” strangler fig in our area, sprouting on a host tree, and dropping its roots to the ground, wrapping the host in a “strangler” embrace in the process.  Ficus microcarpa is an unwelcome invasive exotic in natural areas.  One big “mother tree” can spawn many smaller-scale strangulations in its vicinity. 

A double tree. The larger light-colored individual on the right is a tamarind. The smaller darker green partner is a Ficus microcarpa on the tamarind.

How do you distinguish between Ficus microcarpa and the native Strangler Fig, Ficus aurea

Double your stranglers…this is a mix of F. aurea and F. microcarpa roots, competing to be #1 strangler.

Easy.   Ficus microcarpa lives up to its name by having micro fruits, its little figs ¼” in diameter, vs. twice as big in F. aurea, which also has larger leaves, say, 1.5” wide or wider, vs. about an inch wide and 2.5 inches long, and thick.  

Microcarpa fig and a dime

 Ficus microcarpa is so prone to thrips infestation that you can use the insect damage to help with identification, the thrips causing leaves to fold double and to deform with ugly spotting and crinkles.   Interestingly, however, ‘Green Island’ is generally free of thrips, and is also free of fruits.

Distinctive thrips damage

All of that is context for the cool thing.  Here it is.  How many plants do you know to use two-step seed delivery?  One step for long distance, then the second step local.  Today’s fig has spread all over the tropical world, and it then manages to sub-deliver its seeds into the nooks and crannies of host trees, or into cracks in concrete I-95 overpasses.   Its two step delivery was figured out back in 1991  by ecologists Sandra Kauffman and collaborators.   Birds who eat the figs handle the long distance airmail responsibilities. Toucans like them.  Then ants take over like creepy little mail carriers.  The seeds pass through the birds’ digestive systems with a layer of nutritive “ant food” intact ready to pay for ant services.   That layer is thin and hard to see, although the photo below captures it as the clear outer layer by the line on the right side of the seed.

Seed with ant food visible by the line


 
10 Comments

Posted by on September 3, 2021 in Uncategorized

 

10 responses to “Indian Laurel Fig Has Two-Step Delivery

  1. Chris Lockhart

    September 4, 2021 at 3:59 pm

    Nice write up. BTW, I learned a new tip to distinguish our two native figs. If you take a leaf, fold it over tip to base, the golden fig/ Ficus aurea will match pretty closely. For F. citrifolia, the base is wider than the apex, so you will see some extra tissue on both sides. Cool, eh? We no longer need to look if the fruit is stalked or not. 🙂

     
    • George Rogers

      September 5, 2021 at 8:59 am

      Nice tip. Will try. I’ve never encountered it this far north? On the FL east coast, what’s the farthest north you’ve seen? The USF Atlas shows a little in Broward.

       
      • Chris Lockhart

        September 5, 2021 at 5:00 pm

        Hey George, Yes, I see that there’s a record from along Lox Rd in Broward, west of Deerfield Bch. I don’t recall seeing it in PBC. Sounds like time for a field trip! 🙂

         
      • George Rogers

        September 10, 2021 at 6:47 pm

        good idea!

         
    • Steve Woodmansee

      September 6, 2021 at 4:01 pm

      Another tip for distinguishing the two native Ficus species vegetatively is that the stipule sheath surrounding the emergent leaf is typically red in F. citrifolia, and green in F. aurea.

       
      • Chris Lockhart

        September 6, 2021 at 4:55 pm

        Ahh. Good to know. Thanks, Steve.

         
      • George Rogers

        September 10, 2021 at 6:47 pm

        Thanks Steve…if ever I get around F citrifolia again —-so far south!—will try those tis

         
  2. Steve Woodmansee

    September 6, 2021 at 4:08 pm

    I love figs. I took a fig seminar taught by Dr. Doyle McKey and his wife Dr. Martine Hossaert while I was studying at the Univ. of Miami. Martine was doing all kinds of cool work with the figs and fig wasps and it was a strong argument toward co-evolution concepts in its day (this would have been in the early 90s; Doyle studied Acacias and their ant cohorts). I remember learning about this dual dispersal mechanism then. I worked at the Charles Deering Estate around the same time, and there were two enormous Ficus microcarpa sentinels at the park entrance. Apparently, they didn’t like hurricanes, and both were killed by Hurricane Andrew in 1992. I recall seeing young Ficus trees sprouting from up under the eaves of the historic stone house since birds do not poop upwards, the seeds had to have been brought there by ants.

    George, have you written about the fig wasp relationships with figs?

    Great article as always.

     
    • George Rogers

      September 10, 2021 at 6:46 pm

      Hi Steve, Great to hear from you. Interesting you crossed paths with Doyle McKey. I did not know him personally, but do remember him from Michigan in the 70s. He was a student among a wild group of ecologists doing eye-opening research on tropical plant-ant relationships. Way back in the blog a few years ago is an entry on the figs and wasps. How are things going? BTW, do you recall any easily visited sites in PB or Martin Co for Nephrolepis biserrata growing naturally?

       
      • Steve Woodmansee

        September 13, 2021 at 10:34 am

        Hi George, Doyle (and beer) greatly inspired me as a young undergrad, and I was especially impressed by Doyle’s being active in his community (much like yourself). At the time, I found too few academics at Univ. of Miami were active in our community.
        I figured you might have written a blog post on figs and wasps, I will try and dig it up.
        All is well here in hot and steamy Miami.
        Regarding Nephrolepis biserrata in Palm Beach or Martin County, it should be at Rocky Point Hammock, Peck Lake Park, and neighboring Seabranch Preserve State Park, likely in the baygall and/or hammocky areas, and at Peck Lake Park, near the boardwalk, and at Rocky Point, near the trail that leads through the hammock.

         

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