Use of the rank of forma

[Richard Jensen]

On this matter, I agree with Stuessy (1987. Plant Taxonomy. Columbia
U. Press: pages 186-187; table on page 189).  Although Stuessy provides
both sides of the argument, I read him as indicating that this is not a
very useful rank in the hierarchy.  I think it unnecessary to formalize
such local variants (the oak literature if full of formae based on minor
variations in leaf and acorn shapes; all appear to be nothing more
than local variations within a species).

Recognition of these may be important.  I suspect that Harlan's concept of
'land-races' in important crops, such as rice and sorghum, is
roughly equivalent to the form.  Some of these land-races are of
considerable agricultural importance, but they differ from conspecifics in
minor ways and are fully cross-fertile with each other.

But, to quote Stuessy, "And so the dialogue goes."  Some believe forms
warrant formal recognition and others simply refer to them as the ones
with white flowers, or shallow leaf sinuses, or sub-globose acorns, etc.

Richard J. Jensen      |   E-MAIL: rjensen at saintmarys.edu
Dept. of Biology       |   TELEPHONE: 219-284-4674
Saint Mary's College   |   FAX: 219-284-4716
Notre Dame, IN  46556  |