Sabal sp. ID (Skyway Bridge Rest Area on I-275)

[GoatLockerGuns]

I saw these two nice looking Sabal sp. palms on the Skyway Bridge causeway today in St. Petersburg, Florida.  I was thinking Sabal bermudana...anyone have any ideas?  The seeds were bigger than Sabal palmetto, but not quite as big as Sabal mexicana.  Also, the crown was not as "compact" as Sabal palmetto (one of the pictures shows Sabal palmetto palms in the background for comparison).  The seeds were clumped more tightly together on the drupe than Sabal palmetto as well (like grapes).

 

[teddytn]

Great shot with palmetto in the background for comparison. Not sure what they are, the trunks are fantastic though! 

[idontknowhatnametuse]

Looks like Sabal Causiarum

[RJ]

By guess would be s. Bermudana based on the seed stalks. Image below is from palmpedia 

 

https://www.palmpedia.net/wiki/Sabal_bermudana

 

[GoatLockerGuns]

4 hours ago, idontknowhatnametuse said:

Looks like Sabal Causiarum

I was considering that as well; however, I have held the seeds/fruits in my hand.  They seem too large for Sabal causiarum. I just collected some Sabal causiarum seeds at Kopsick, so I had them on hand for comparison.  They are smaller.

[GoatLockerGuns]

4 hours ago, RJ said:

By guess would be s. Bermudana based on the seed stalks. Image below is from palmpedia 

Yeah, that was one of the pictures I was looking at initially.  Sabal bermudana is still on the top of my list, but there is much variability in the genus.  There are a lot of Sabal spp. that I am not familiar with as well.  The description of "pair-shaped" fruits for Sabal bermudana matches the fruits I collected too.

[Fusca]

2 hours ago, GoatLockerGuns said:

Yeah, that was one of the pictures I was looking at initially.  Sabal bermudana is still on the top of my list, but there is much variability in the genus.  There are a lot of Sabal spp. that I am not familiar with as well.  The description of "pair-shaped" fruits for Sabal bermudana matches the fruits I collected too.

Rich, @aztropic has a mature Sabal bermudana in his garden.  Maybe he can weigh in an opinion.  He posted a pic of his palm recently with the fruits and trunk.

 

[Zeeth]

Kinda surprised there's anything rare over there at all. I think the trunk is smoother than I'd expect for S. bermudana. Doesn't quite look robust enough for S. domingensis or S. causiarum though. I'm going to throw a vote in for S. maritima. 

[RJ]

3 hours ago, Zeeth said:

Kinda surprised there's anything rare over there at all. I think the trunk is smoother than I'd expect for S. bermudana. Doesn't quite look robust enough for S. domingensis or S. causiarum though. I'm going to throw a vote in for S. maritima. 

I thought about that too, but doesn’t maritima  have silver speckling on the leaf petioles?

Edited November 26, 2022 by RJ

[Zeeth]

2 hours ago, RJ said:

I thought about that too, but doesn’t maritima  have silver speckling on the leaf petioles?

Looking closely it does look like there is some on the newer leaves, particularly at the base of the petioles. 

[GoatLockerGuns]

Here is the Google Maps Street View of these palms (from March 2021):

https://www.google.com/maps/@27.6484441,-82.6756203,3a,75y,78.31h,90.73t/data=!3m6!1e1!3m4!1siXOhOlXhOHJ-kFYJLwt7yQ!2e0!7i16384!8i8192

[GoatLockerGuns]

On 11/26/2022 at 10:53 AM, Zeeth said:

I'm going to throw a vote in for S. maritima. 

Sabal maritima would definitely be a cool find.  It seems a little "exotic" for an interstate rest area though (but I guess Sabal bermudana could be considered "exotic" as well).  I am not seeing the scale that you are seeing and, if it is there, it doesn't seem to be as prominently displayed as those young petioles pictured on Palmpedia.  Also, I am not clear about the seed size for Sabal maritima, or whether what I collected matches up with that species.  I would not rule it out though.

[GoatLockerGuns]

Here is a seed size comparison of seed from the palms in question in relation to other Sabal spp. seeds.  These were the only Sabal spp. seeds I had on hand.  I picked the Sabal palmetto, Sabal minor, and Sabal mexicana seeds from local palms growing in San Antonio, Texas in early November.  I picked the Sabal mauriiformis and Sabal causiarum seeds from labeled palms growing at Gizella Kopsick Arboretum in St. Petersburg, Florida over Thanksgiving.  Obviously, the seed labeled Sabal sp. 'Skyway Bridge' is from one of the palms in question.  The reason the sizes look a little smaller in the picture (as apposed to what I listed) is due to an approximate half inch height difference between the t-square ruler and the paper towel (and the point of view of the camera to some extent).  I placed the seeds directly on the ruler to get more precise measurements.

Sabal palmetto - 5 1/2 mm

Sabal minor - 6 1/2 mm

Sabal mauritiiformis - 7 1/2 mm

Sabal causiarum - 8 1/2 mm

Sabal sp. 'Skyway Bridge' - 10 mm

Sabal mexicana - 12 mm

[GoatLockerGuns]

On 11/26/2022 at 10:53 AM, Zeeth said:

I think the trunk is smoother than I'd expect for S. bermudana. Doesn't quite look robust enough for S. domingensis or S. causiarum though. I'm going to throw a vote in for S. maritima. 

From the research of I have conducted (which included, but was not limited to, going through many pictures on the interwebs, the accuracy of many being somewhat suspect), I feel like these palms may be one of the "Caribbean Three" as you suggest (i.e., Sabal causiarum, Sabal domingensis, or Sabal maritima).  I have a hard time telling the difference between the three by trunk or frond appearance alone though.  Zona (1990) specifically calls out the "ringed" appearance of the Sabal bermudana trunks; therefore, I am tentatively ruling that one out due to the "smooth and gray" appearance of the Skyway Bridge specimen trunks (even though the fruit and seed descriptions could be a match). Of the 20+ seeds that I collected from one of the Skyway Bridge specimens (only one had fruit present), there was some variation in size.  Most were in the 10 mm diameter range, but some were in the 8 1/2 mm to 9 mm diameter range.  Of the 15+ Sabal causiarum seeds I collected from Kopsick (a labeled palm; I am assuming the label was accurate), all were fairly uniform around 8 mm to 8 1/2 mm in diameter.  I currently feel like Sabal domingensis or Sabal maritima are the two most likely candidates (although, the upper seed diameter sizes are a bit larger than what Zona presents for Sabal maritima).  The reported "scale" on the petiole of Sabal maritima would be another visual indicator; however, I really do not what to look for in that regard.  Also, the petiole pictures of the "Caribbean Three" that I have found all look so similar, I really have a hard time telling them apart.

Here is what Zona (1990) identifies as truck and seed diameter characteristics for the aforementioned Sabal spp.:

Sabal bermudana: Trunk: gray, obscurely to prominently ringed with leaf scars; Seed: oblate-concave, 7.5-12.5 mm in diameter.

Sabal causiarum: Trunk: smooth and gray; Seed:  oblate concave, 5.9-7.8 mm in diameter.

Sabal domingensis: Trunk: smooth and gray; Seed: oblate concave, 8.0-10.4 mm in diameter.

Sabal maritima: Trunk: gray, with or without persistent leaf bases; Seed: oblate concave, 6.5-9.7 mm in diameter.

[Bigfish]

I'm putting in a vote for S. causiarum.  In this picture, you can see the characteristic papery ligule at the base of a new leaf. 

 

 

[GoatLockerGuns]

1 hour ago, Bigfish said:

I'm putting in a vote for S. causiarum.  In this picture, you can see the characteristic papery ligule at the base of a new leaf. 

Yeah, I noticed that too.

Another comparison photo below with a germinated Sabal sp. 'Defuniak Springs' seed (seed courtesy of @Bigfish).  The Sabal sp. 'DeFuniak Springs' seed is approximately 8 mm in diameter (in between Sabal mauritiiformis and Sabal causiarum from the previous picture).

[GoatLockerGuns]

On 12/5/2022 at 5:56 PM, Bigfish said:

I'm putting in a vote for S. causiarum.  In this picture, you can see the characteristic papery ligule at the base of a new leaf. 

 

On 11/26/2022 at 10:53 AM, Zeeth said:

I'm going to throw a vote in for S. maritima.

Identifying Sabal spp. can be so hard sometimes.  Papery ligules are typically used to ID Sabal causiarum by enthusiasts (at least, anecdotally); however, Zona (1990) did not use them as a defining morphological differentiation trait for identification (I can't seem to find mention of ligules at all in his monograph).  Fruit/seed shape and size was more readily utilized in his paper for identification.  According to Zona (1990), Sabal causiarum fruits have a "...spherical or occasionally oblate-pyriform" shape.  The fruits that I collected from this specimen were moderately to strongly pyriform (i.e., pear shaped), and most (but not all) were larger in size than what is reported in Zona (1990) for Sabal causiarum.  The fruits that I collected did not appear "spherical" to me, and there were more pyriform fruit present than what I would consider "occasional."

The fruit/seed shapes and sizes seem to be more indicative of Sabal bermudana, Sabal domingensis, or Sabal maritima (which all have larger seeds, and more pyriform fruit characteristics).  Yet, at least one of these Skyway Bridge palms displays some papery ligules, which is an anecdotal indicator of Sabal causarium.  I am not ruling out Sabal causiarum, but I am not yet convinced either (at least, not based on a few papery-looking ligules alone).  Also, "speckling" or "scale" on the base of the petioles is supposedly an anecdotal trait used to identify Sabal maritima.   I am not sure what this actually looks like, as I have not found clear pictures of it occurring on properly identified Sabal maritima specimens.  @Zeeth says he was able to see it in one of the pictures I posted.   I can not find reference to this trait in the Sabal maritima entry in Zona (1990) either.  I wonder if Sabal maritima also displays some form of papery ligules?

[GoatLockerGuns]

Some more Sabal sp. seeds for comparison.  I received 25 Sabal maritima and 25 Sabal yapa seeds from @NatureGirl.  The Sabal yapa seeds were fairly uniform, all measuring between approximately 5 1/2 mm to 6 mm in diameter.  The Sabal maritima seeds were all over the place though, measuring anywhere from approximately 6 mm (smallest) to 10 mm (largest).  Most of the Sabal maritima seeds were in the 8 mm to 9 mm range though.

My updated seed size approximation chart below:

Sabal palmetto - 5 1/2 mm (roughly uniform)

Sabal yapa - 5 3/4 mm (average - varied between 5 1/2 mm and 6 mm)

Sabal minor - 6 1/2 mm (roughly uniform)

Sabal mauritiiformis - 7 1/2 mm (roughly uniform)

Sabal sp. 'DeFuniak Springs' - 8 mm (roughly uniform)

Sabal maritima - 8 mm (average - varied between 6 mm and 10 mm)

Sabal causiarum - 8 1/2 mm (roughly uniform)

Sabal etonia 'Miamiensis' - 8 1/2 mm (roughly uniform)

Sabal sp. 'Praha' - 8 3/4 mm (average - varied between 8 mm and 9 1/2 mm)

Sabal sp. 'Skyway Bridge' - 9 mm (average - varied between 8 mm and 10 mm)

Sabal mexicana - 11 mm (average - varied between 10 mm and 12 mm)

I guess that Sabal maritima is still in the running (based on the top end of their seed size); however, the "low end" of their seed size did not match what I collected from the Sabal sp. 'Skyway Bridge' specimen (same batch size of 25 seeds; none were smaller that 8 mm).  From the reported seed size of Sabal domingensis (Zona 1990), along with overall presentation of the palm, it is currently at the top of my list (I do not have any actual Sabal domingensis seeds to measure).  That said, I guess Sabal bermudana and Sabal mexicana might also be contenders based on their seed sizes alone.

[RJ]

What  zone is this location in? Sabal domingensis is pretty frost tender from my understanding. (Bud hardy but leaf tender) This most recent cold snap might a good time to investigate what if any damage may have occurred…. 
 

Edit:  we’ll just realized this was n FL as I re read the initial post. I was thinking these were in TX. 

Edited December 24, 2022 by RJ