Alocasia and Xanthosoma : a query

[surajit koley]

In a recent thread I and Pudji Ji have initiated a discussion on a certain aroid member. This is the first time I come across the genus Xanthosoma. I searched for the genus in FI, FBI, BP, BoB&O, even I tried with synonyms of Xanthosoma sagittifolium, but to no avail. Searched the internet, again couldn't find much info. Specially regarding the species distribution of Xanthosoma in our country, India.

In fact very little documents can be found on Xanthosoma related to India. One doc., related to antioxidants in X. sagittifolium, informs that the authors collected the specimen from Western Ghats. EFI has two, one from Coimbatore and the other from Uttarakhand. Bangladesh also reports presence of Xanthosoma spp.

An old, yet interesting document on Alocasia macrrorhiza and other species can be found at - http://137.132.71.21/dna/docs/cf944ffddd72f5381003c0758c52dc83.pdf which informs the author did receive Xanthosoma material from Calcutta. It is further more interesting that FoC or FoP or even FoNA doesn't feature Xanthosoma.

Morphological difference, based on leaf characters, between Alocasia and Xanthosoma can be found in a few website. But those authors themselves are not very sure about the differences they have recorded there!

Yet, I think we might have some Xanthosoma hidden in the posts submitted to eFI, recently or in past.

Many thanks to Pudji Ji for drawing my attention to a new line of thought.

In this pretext I would request members+moderators to please provide species list of Xanthosoma found in India and their identifying characters.

Thank you

Regards

[surajit koley]

In continuation with the discussion in the other thread, with Pudji Ji, I would request to draw attention to few posts, first the cases I have submitted so far. It is to be noted that the identities of Alocasia indica Schott and A. macrorrhiza Schott (of BP or BoBO) are not clear to me. I take those are synonymous.

I think my posts https://groups.google.com/forum/?hl=en&fromgroups#!topic/indiantreepix/ZFkSSz-krpk and https://groups.google.com/forum/#!topic/indiantreepix/pQBZMwG5hoE are Alocasia.

Another one that I have recorded recently https://groups.google.com/forum/#!topic/indiantreepix/tyNUNT6diR8 may be Xanthosoma.

I request all to record your views.

Thank you

Regards

[surajit koley]

This is what I know as Alocasia fornicata (Roxb.) Schott. I think the plant features satisfy FI, FBI, BP, BoBO and Wight illustration T.792.

Since this plant, photographed today, is growing on a wall it is rather a small one and the stock is visible. In all previous cases I have never seen the stock above the ground level. Of-course they do not get a free hand to grow undisturbed though no part of this Alocasia is edible.

My next post will be another Alocasia.

Thank you

Regards

[surajit koley]

This is what I know as Alocasia indica Schott. Again I have never seen stock growing above the ground, for they are often cut and used for several purpose.

Thank you

Regards

[surajit koley]

Now, this is the third plant. What would be its identity?

Thank you

Regards

[surajit koley]

The third plant in this thread is definitely Xanthosoma species, possibly Xanthosoma sagittifolium (L.) Schott. Attached here detail photographs of its flower.

In this set of photographs I have marked two plates. Please correct me if I am wrong. The last plate features leaves of A. fornicata(top-left), C. esculenta (top-right) and the plant in question, Xanthosoma (bottom).

Again I thank Pudji Ji for his immense help, but his points regarding the difference between Alocasia, Colocasia and Xanthosoma, in the following threads, are still unclear to me -

• https://groups.google.com/forum/?fromgroups#!topic/indiantreepix/FrcqDVNQ95o
• https://groups.google.com/forum/?fromgroups#!topic/indiantreepix/NOC9yAXhgr8
• https://groups.google.com/forum/?hl=en&fromgroups#!topic/indiantreepix/pUNGKnlyy_8
  

I would appreciate it very much if Pudji Ji and Dr. Bruggeman as well as moderators and members offer their views regarding this.

Thank you

Regards

[J.M. Garg]

Forwarding again for any assistance in the matter please.

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With regards,
J.M.Garg

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[surajit koley]

Leaves sagittate or not is not at all important, caudex also is less important to identify a Alocasia or Xanthosoma. It takes a detail of spadix to identify any Alocasia or Xanthosoma species. Otherwise the identification is bound to be wrong very often than not!

Since the spadix of this species doesn't have any appendix this is not Alocasia. But which Xanthosoma is it? Our group has expert(s) on Xanthosoma sagittifolium (L.) Schott .... who can identify the species merely by leaves! Ironically he/they is/are silent on this thread. The silence may mean that it is not X. s. .... or two more options I don't like to write here.

Unfortunately I do not have description of Xanthosoma robustum Schott, except http://www.hear.org/pier/species/xanthosoma_robustum.htm, where no detail of spadix can be found. While the TPL and GRIN recognize Xanthosoma robustum Schott as an accepted name the PIER and SMITHSONIAN, unlike TPL, think it is the accepted name of X. roseum Schott.

As per FLORA BRASILIENSIS -

1. X. sagittifolium (L.) Schott = Caudex arborescence; foliorum petiolus usque 1m., lamina 4-5 dm longa ...... ovaria ovoidea, albida, stigmate flavo coronata......
2. X. mafaffa Schott = Caudex abbreviatus; ....  ovaria ovoidea annulo stylino violaceo atque stigmate aureo 3-4 lobo instructa.....
3. X. violaceum Schott = Caudex abbreviatus; .... 
4. X. atrovirens C.Koch  et Bouché = Caudex abbreviatus; ....feminea cylindroidea quam mascula 3.5 plo breviore lutea, mascula sterili pallide rosea....

All the above are synonyms of X. sagittifolium (L.) Schott, where the ovaries can be whitish, yellowish or even golden (against green in Curtis's) and sterile stamens can be pale pink!

So, finally it is X. sagittifolium (L.) Schott unless expert(s) identify it as Xanthosoma robustum Schott

Thank you

Regards

[surajit koley]

At least two species were reported from West Bengal as per paper found in the net - 1) X. sagittifolium (L.) Schott and 2) X. maximiliani Schott. The later has identified by " spathae tubus intus purpureo-sanguineus, lamina extus sanguinea" (vide Flora Brasiliensis).

It is to be noted that leaves of X. s. are tasty vegetable (vide Curtis's, Engler).

Thank you

Regards