[Arisaema-l] Arisaema root structure

[Henry]

The Genus Arisaema: A Monograph for Botanists and Nature Lovers by Guy and Liliane Gusman says:

"Arisaemas are herbaceous and the aerial shoot develops from a thickened, subterranean stem. Although it is usually buried in the soil and thus hidden, the stem is one of the main parts of an arisaema, important for both food storage and reproduction. Arisaema stems are either tubers or rhizomes." --from the chapter Morphology, p. 15
[The bold text is as in the book.]

Figure 1 in the Morphology chapter shows Arisaema serratum, they label the underground part a "subglobose stem." Also in the same illustration they label the underground part of Arisaema speciosum as "elongated stem." From page 13.

On each species described later in the book there is a sub-head for Subterranean stem. They list most as "subglobose tubers."

Arisaema dracontium is listed with an "elongated-globose tuber."

Arisaema triphyllum is listed with a "globose tuber."

Arisaema speciosum is listed as "a tuber cylindrical, annulate and horizontal."

In flipping through the book I did not find any having a subterranean stem described as a rhizome.

I would be happy to check a certain species if some doesn't have the book.

--Henry Fieldseth
Minneapolis, Minnesota, USA, Zone 4 (but almost zone 5 on the new maps)



--- On Sun, 4/22/12, Erick Adams <rogthegoat at hotmail.com> wrote:

From: Erick Adams <rogthegoat at hotmail.com>
Subject: Re: [Arisaema-l] Arisaema root structure
To: arisaema-l at science.uu.nl
Date: Sunday, April 22, 2012, 8:27 AM





Arisaema taxonomist Jin Murata published a paper called Diversity in the Stem Morphology of Arisaema.
I have not read the paper proper but the opening abstract refers to the pertinent 
underground bits as an "abbreviated subterranean stem".
 
I think that's a good way to put it so we don't have to figure out where a tuber begins, 
a corm ends and to what degree they are rhizotamous. Hoozah.
 
It also provides a mildly amusing acronym for making bad Arisaema jokes.
 
 
Erick 
 
Zone 6 - Rhode Island, USA
 
 
 
Date: Sun, 22 Apr 2012 07:58:44 +0100
From: petersirises at gmail.com
To: arisaema-l at science.uu.nl
Subject: [Arisaema-l] Arisaema root structure

What is the botanical term for the storage organ on an Arisaema please?


I think of it as a tuber which is a swollen root such as a potato has, but a potato is a dicot. Is the 'tuber' root or stem? Were it stem then surely it would count as a rhizome -as with a bearded Iris?  Others here are calling it a corm, I associate corms with Irids and regard them as stems surrounded by compressed leaves.

An article by Tony Avant refers to it as a pseudo tuber...


Peter (UK) 		 	   		  

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