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  Leaf vein nomenclature
From: a san juan kalim1998 at yahoo.com> on 2005.06.25 at 04:22:18(13047)
I was looking at a key for Philodendrons, and came
upon a numbering system for leaf veins that I'm not
sure about.

From: "Derek Burch" derek at horticulturist.com> on 2005.06.25 at 11:57:31(13050)
This looks much more complicated than it really is. Using your example, it
means that the usual number of veins per side is six to nine. But in
examining a lot of specimens that in all other characters fit the species
description, the botanist found occasional examples with as few as five or
as many as ten veins per side.
Particularly when used in a key, this prevents a plant being excluded from
its correct identification because it is aberrant in a single small
character. As I am sure you know, you should always read both parts of the
couplet that makes up that stage in the keying process, and select the path
that best fits the "unknown" plant even if it isn't an absolutely perfect
From: Aroideae at aol.com on 2005.06.25 at 12:11:17(13051)
it means that there are normally 6 or as many as 9 primary lateral veins on
either side of the midrib of the anterior lobe, which is that portion from the
point of petiole attachment to the apex of the leaf blade. the numbers in
parenthesis mean that there are rarely as few as 5 primary lateral veins per
side or as many as 10, usually meaning that only one specimen had 5 and one
specimen had 10.
From: a san juan kalim1998 at yahoo.com> on 2005.06.26 at 06:15:27(13056)
Ahhh!!!! Thanks to the people who answered...now that
it's explained, it seems so self-evident!

--- Derek Burch wrote:

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