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Andreas Wistuba

Squamellaria imberbis (Vanua Levu)

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In his 1991 Monograph (BLUMEA — VOL. 36, No. 1,1991) Jebb decided to put Squamellaria wilsonii that is described from Taveuni (Fiji) into Squamellaria imberbis, which was described from Vanua Levu.

I visited two Squamellaria sites on Vanua Levu and one on Taveuni and I saw consistent considerable differences between both species.

Jebb wrote "...Squamellaria wilsonii was formerly distinguished by its shorter corolla, lobes, longer relative to the tube, stamens longer than filaments, fruit more globose, py- renes less hooked, and leaves more acute and gradually attenuate (Beccari, 1886), and longer calyx limb (Smith, 1988). In the light of further collections and study of fresh material, these differences have proved insignificant, or due to developmental stages, or the vagaries of drying...." 

 

Actually, I am not sure what is meant by "calyx limb". However the tube that is formed by the fused sepals is much longer in Taveuni plants (!!!) and this is nicely pictured in Becarri. It is not at all a drying artefact or due to various developmental stages:

 

post-1-0-58042300-1409461759.png

 

 

S. imberbis:

 

post-1-0-58745700-1409462852_thumb.jpg

 

 

S. wilsonii:

 

post-1-0-57265500-1409462848_thumb.jpg

 

post-1-0-94376100-1409462839_thumb.jpg

 

 

Another difference, not mentioned by Jebb but nicely pictured in Becarry (see above), is the petiole length of both species. Plants from Vanua Levu consistently have much shorter petioles:

 

Upper leaf, S. wilsonii, lower leaf S. imberbis:

 

post-1-0-46877900-1409462843_thumb.jpg

 

 

Interestingly, in situ I found that the caudex of Squamellaria imberbis is much different from the caudex of Squamellaria wilsonii (I decided to use this name from now on for the Taveuni plants). Squamellaria imberbis in most plants shows contractions around the caudex where the entrance holes are located, much as Squamellaria thekii.

With Squamellaria thekii, it shares another feature: Older plants become multi-polar!

 

Plants of S. imberbis on Vanua levu:

 

post-1-0-51674300-1409463148_thumb.jpg

 

post-1-0-81166800-1409463153_thumb.jpg

 

post-1-0-58441800-1409463159_thumb.jpg

 

post-1-0-29418100-1409463169_thumb.jpg

 

post-1-0-43482600-1409463175_thumb.jpg

 

 

Old multi-polar plant:

 

post-1-0-37117900-1409463164_thumb.jpg

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Table  XLVI

 

Squamellaria imberbis Becc.  Drawings all done from a specimen collected during the U.S. Exploratory

                                                   Expedition to the Fiji Islands and stored at the Kew Herbarium

fig. 1   Portion of a branch, actual size

fig. 2   Well developed bud  (3X)

fig. 3   Corolla open and extended  (4X)

fig. 4   A squamella from the base of the corolla, much enlarged

fig. 5   Anther from the back  (6X)

fig. 6   Anther from the front  (6X)

fig. 7   Stigma, much enlarged 

fig. 8  Calix and ovary sectioned lengthwise  (8X)

fig. 9  Mature fruit, dry  (4X)

fig. 10  Pyrene sectioned lengthwise  (4X)

fig. 11  Whole pyrene viewed from the side  (4X)

fig. 12  Seed cut lengthwise to show the embryo  (8X)

 

Squamellaria Wilsonii Becc.  Drawings from a specimen collected by Horne on the Fiji Islands, No.1139,

fig. 13   Leaf, actual size                                                                                                  in the Kew Herbarium.                                                                                                          

fig. 14   A bud  (3X)

fig. 15   Open and extended corolla of a well-developed bud  (4X)

fig. 16   Longitudinal section of the ovary and calyx  (4X)

fig. 17  Transverse section of the ovary  (4X)

fig. 18  Two anthers viewed from the back with the style in place, much enlarged

fig. 19  Mature fruit, dry  (4X)

fig. 20  Pyrene viewed from the side  (4X)

fig. 21  The previous pyrene sectioned lengthwise to show the embryo

 

Above is the translated labeling for Beccari's Table XLVI and below an easier to read copy of Table XLVI

 

(For newer members of the forum let me remind you that a full set of Beccari's Tables with translated labeling is available as two PDF downloadable files on my website:  franksantplants.com)

post-22-0-66062100-1409474636_thumb.jpg

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Just an addition:

 

The differences in pyrene shape as pictured by Beccari (hooked vs. not hooked, 11, 11 vs. 20, 21) also holds true nicely.

Sorry I did not take pictures this morning as I rather hurried to get done with the few seeds I have.

 

Frank:

 

Thank you VERY MUCH!!!

 

These translations really will make a big difference in making Beccari's invaluable contribution to Ant Plant knowledge available to the enthusiast's community who are not able to speak Italian.

 

Meanwhile, I am a big fan of Beccari ;)

 

All the best

Andreas

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It remains to be proved that these examples do not represent the extremes of a cline of characters. It would also be interesting to see how variable will be the progeny produced from parent plants. Do these 'forms' freely interbreed? Vanua Levu sits very close to Taveuni (closest about 6.5 km.), so there surely is some genetic exchanges between the various local populations. Of course Philidris nagasau will tend to control seed distributions within the territories of each nest. 

  Also, some of these Vanua Levu tubers hint that there may be some Sq. major genes in their mix. 

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It remains to be proved that these examples do not represent the extremes of a cline of characters. It would also be interesting to see how variable will be the progeny produced from parent plants. Do these 'forms' freely interbreed? Vanua Levu sits very close to Taveuni (closest about 6.5 km.), so there surely is some genetic exchanges between the various local populations. Of course Philidris nagasau will tend to control seed distributions within the territories of each nest. 

  Also, some of these Vanua Levu tubers hint that there may be some Sq. major genes in their mix. 

 

The differences in fruits and leaves were absolutely consistent. 

BTW, I saw and photographed ants pollinating the flowers. In fact, they were quite active in the inflorescences! The strange arrangement of anthers just leaves enough space for ants to get to the pollen. If ants are the natural pollinators, then I see little or no chance of pollen getting from one population to another.

Of cause, birds can carry fruit but the populations are quite isolated in the highlands, so this will not be a very frequent event.   

 

Of cause, the differences are not huge but certainly are not artefacts such as it was suggested by Jebb. It remains to everybody to decide whether to treat Squamellaria wilsonii as a good species since it was validly published. 

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These are great photos Andreas, thank you very much.  Those fruits are very interesting.  Unless you or someone else goes back and finds intermediates I am certainly inclined to see these as distinct species.  Some DNA sequences and work for Squamellaria species would be very interesting to see as well.  Who needs a PhD topic and wants to spend some time in Fiji? :)

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If I ever return to Fiji, I will spend more time on Vanua Levu Island. However, to avoid creating confusion when publishing my images, I will continue to follow Jebb's taxonomy but with added data, thus there will be Squamellaria imberbis "Taveuni Island" and S. imberbis "Vanua Levu Island."  I believe there is insufficient evidence to use the name S. wilsonii.   

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