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  Help i.d. these aroids
From: Bob Riffle <71270.3070 at compuserve.com> on 1998.05.12 at 06:15:39(2103)
If any of you more knowledgeable aroiders have the time/energy
could you take a look at scanned photos 132a, 132b, and 132c at
From: plantnut at shadow.net (Dewey Fisk) on 1998.05.12 at 08:35:58(2104)
I do not know what the plants are.... but, I can tell you definitely that
they are not Xanthosoma sagittifolia... X. sagg... has no red in the

From: Bob Riffle <71270.3070 at compuserve.com> on 1998.05.12 at 19:07:25(2107)
<<< X. sagg has no red in the petiole >>>
On my screen the petioles are a deep purple, almost black. But I'm
not arguing . I just don't know; I was told many years ago by
someone I thought knew what he was talking about that the plant(s)
I have were Xanthosoma sagittifolia. He went on to point out how
the leaves differed from those in the Colocasia genus by having
a quite distinct vein encompassing the entire leaf margin, about
1/4 to 1/2 inch from the actual margin. The leaves are a very
deep green, almost with a bluish cast and the petioles vary from
a deep emerald green to that distinctive dark purple that's almost
black. In addition they (the leaves on the ones *I* have) can
attain 6 feet in length with constant warmth, water and fert.
Do you know anywhere on the web a decent photo of what is definitely
X. sagittifolia ?

From: plantnut at shadow.net (Dewey Fisk) on 1998.05.13 at 08:07:36(2109)
>Do you know anywhere on the web a decent photo of what is definitely
>X. sagittifolia ?
>Thanks much for taking the time/trouble ....

No, I do not think I have a photo of X. saggi.... but, I can take one
tomorrow... I have them in the ground that are well over my head. But as
far as the color is concerned... I could be wrong.... but the only color
that I have ever seen on the clone we have here are different shades of
green.... the 'wax' build up on the petioles give it a sort of silver
color but there is no red, maroon or any of the other colors that you

Put it this way.... on my list....... I have offered it... it is
available.... at least the clone we have here.....

Anyone else with any ideas on subject plant?

From: "Julius Boos" <ju-bo at email.msn.com> on 1998.05.13 at 08:26:30(2112)
Subject: Help i.d. these aroids
Dear Folks,
These look like and are what we have been calling X. violaceum since I can
remember; mine where grown from edible corms purchased from a Jamacan
grocery as "red co co`s", BUT--- just last week I came across a plastic bag
of what LOOKED like the same, purplish tubers/corms (purchased at Winn
Dixie) on a table at a commercial plant nursery here in W.P.B., and when I
enquired of the owner what he was going to do with them, was told that a
client was paying him to grow them, and that he already had some sprouting.
He took me to see the growing ones, and I checked to make sure that the
corms/ tubers/rhizomes were the same purplish color, and even checked INSIDE
to see if they were yellow, but they were white fleshed, but to my surprise
the leaves being produced were all-green (NO purple tint on blade OR
petiole) and more rounded, with a thicker texture than "regular" X.
sagittifolia leaves, and were simular to a plant I have grown from the
"yellow malanga" corms/etc. from a Latin store!
SO--- there is all kinds of things going on with these cultivated var`s.,
and I suggest caution when naming them untill SOMEONE reviews the genus!
For now I`d call the plant in the photo X. violaceum.
From: Eduardo <eggon at guarany.cpd.unb.br> on 1998.05.13 at 13:44:46(2114)
Dear Bob,

The pictures 132a, b and c of the ID center are SURELY Xanthosoma
violaceum Schott. It is one of the easiest Xanthosoma to recognize,
because of the purple petioles, somewhat triangular leaves and the basal
ribs usually denuded (at least for 0.5cm) in adult and pre-adult leaves.
Xanthosoma sagittifolium has green petioles (usually with a silvery
color, because of the wax, as Dewey mentioned)and green leaves (ovate in
outline), with the basal ribs never denuded for more than 0.5cm.
Usually, the basal lobes in X. sagittifolium are well developed and
frequently overlapping one each other. The basal lobes in X. violaceum
are less developed and do not overlap, because of the open sinus. The
inflorescences are quite different too, but they rarely flower.

I hope it helps,


From: Bob Riffle <71270.3070 at compuserve.com> on 1998.05.13 at 19:13:22(2118)
Oh, it helps greatly, Eduardo, especially the mention of leaf
shape. Forgive my ignorance here but just what are "the basal
ribs?" I have no "picture" in my mind what this could be. Do
you mean the veins.

X. violacea was my second thought as to the i.d. of these beauties,
and now it seems to be confirmed.

Would the Demi Bown book AROIDS help me solve some of these taxonomical
quandaries? I have it on order from amazon.com for a number of weeks
now but, so far, they've not been able to locate it ....

Thanks much ....

From: Bob Riffle <71270.3070 at compuserve.com> on 1998.05.13 at 19:17:32(2119)
Well, I gotta get one of those from you--if for no other
reason than to see what a true X. sagittifolia really is. Mr.
Boos and Eduardo seem to think what I have (and what is pictured
at the Mansell site) is X. violacea. That was my second thought
about what I have. If so, there are many cultivars here in
Houston. I recently went to a mom-and-pop place at which the
hubbie specializes in growing "rare" things, most of which he has
no idea as to the identity. He had a number of plants whose leaf
color (not to mention petiole color) ranged from the dark, almost
bluish green I have, to almost black. He thought they were Colocasia
forms. I couldn't argue with him, but the leaf shape and size were
so alike my X's that I feel these are forms of it.

From: Bob Riffle <71270.3070 at compuserve.com> on 1998.05.13 at 19:21:33(2120)
Oh, Eduardo, DECIDEDLY there needs to be taxonomic research done on
these things! Do you know of anyone or group who IS working on
them. It's rather hard to believe that it hasn't already happened
because of the extraordinary beauty of these things ....

From: "Julius Boos" <ju-bo at email.msn.com> on 1998.05.14 at 15:59:10(2131)
-----Original Message-----
To: ju-bo@msn.com
Date: Wednesday, May 13, 1998 10:08 PM
Subject: Re: Help i.d. these aroids
Dear Bob,
The commoner blackish Aroids generally seen for sale are mostly Colocasia
sp. To tell them apart at a glance from the available Xanthosoma species,
look at the area where the two upper lobes of the leaf come together on
their way down to the petiole (stem). In Colocasias they will join before
they touch the petiole (peltate leaf blade), while in Xanthosomas they end
at the main ribs BEFORE these ribs continue down to the top of the petiole
(sagittate leaf blade). Hope this helps.
From: Bob Riffle <71270.3070 at compuserve.com> on 1998.05.14 at 18:27:59(2132)
Julius, thanks to you and Eduardo this MAY be coming together (i.e.,
clear) for me now. You are saying that Colocasia leaves are peltate
and Xanthosoma leaves are not (?) I just checked and both HORTUS III
and the Griffiths' DICTIONARY mention that Colocasia leaves ARE peltate
but does not say that Xanthosoma leaves are NOT peltate. And what would
be the term for petiole attachment that is NOT peltate, if there IS one?
I can't even find such a term in the Harris/Harris book. Seems to me
there needs to be one, eh?

Thanks much; this is all very much fun ....

From: "Julius Boos" <ju-bo at email.msn.com> on 1998.05.15 at 08:23:38(2136)
Dear Bob,
The commoner (in cultivation) species of Xanthosomas have sagittate leaves,
while the commoner species of Colocasias (and Alocasias) have peltate
leaves. As in everything to do with Aroids, there are exceptions to these
rules, as there are even cultivars of Taro (Colocasia) in Hawaii with
sagittate leaves ("Piko" types, according to Deni Bown`s book) where they
"have their blades lobed to the navel or piko". She also has good
illustrations of these two types of leaves, Colocasia and Xanthosoma. By
the way, Aroiders out there, any more news on a re-print of this wonderful
book??? There are also smaller species of Xanthosoma that I`ve seen from
S. America with peltate, pubescent leaves. This may explain why no one has
stated that Xanthosoma leaves are NOT peltate. There would be many terms
for a petiole attachment that was not peltate, depending on HOW/WHERE it was
Hope that this helps,
From: "Dr. Tom Croat" <tcroat at lehmann.mobot.org> on 1998.05.15 at 08:28:38(2137)
> Date: Thu, 14 May 1998 20:26:40 -0500
> Reply-to: aroid-l@mobot.org
> From: Bob Riffle <71270.3070@compuserve.com>
From: Bob Riffle <71270.3070 at compuserve.com> on 1998.05.15 at 19:02:05(2143)

Dr. Croat, thanks much for this morphological term!

From: Bob Riffle <71270.3070 at compuserve.com> on 1998.05.15 at 19:06:03(2144)
Gosh, I'd like to see some of those Xanthosoma with pubescent leaves!
I think the tropical "evergreen" aroids are among the most dramatic
and beautiful of all landscape subjects, and I'm maniacally hungry
to know and see them all ....

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