Use of the rank of forma

[Thomas Lammers]

At 05:16 PM 10/2/00 -0700, you wrote:

>But at species or above it would be nomenclatural. If Papaveraceae and
>Fumariaceae are both ranked as families, Pteridophyllum can be included in
>one or the other but not both simultaneously.

The placement of a genus in a family is classifatory and has no
nomenclatural implications.  The name of the genus does *not* change if it
placed in this family or that.  Because of binomial nomenclature, the name
of a species or infraspecific taxon DOES change if its classification
changes, to only to a point.  The name of a forma will change if it is
moved from one species to another.  It will *not* change if it is moved
from one subspecies or varietas to another *within the same species*.

A real example:

An occasional yellow-flowered variant of a purple-flowered species was
described as:
Clermontia coerulea f. flavescens E. Wimm. (1953)

H. St. John (1973) distinguished two geographic subspecies within C.
coerulea: subsp. coerulea and subsp. brevidens (Skottsb.) H. St. John.

The yellow-flowered variant belonged to the latter, so H. St. John
published the "new combination" C. coerulea subsp. brevidens f. flavescens
(E. Wimm.) H. St. John.  This violates ICBN Art. 24.1.  Since the name does
not comply with Art. 24.1, Art. 32.1(b) is violated, which means the name
is not validly published.  As such, it is not even a name in the eyes of
the Code (Art. 6.3) and has no status under the ICBN (Art. 12.1).  In
short, it doesn't even exist as a synonym.   The correct name H. St. John
should have used is C. coerulea subsp. brevidens f. coerulea E. Wimm.

>Are you saying that forma alba can be included in both variety virgata and
>variety laxa at the same time?

No.  Only that both varieties might have white flowered morphs.  If so,
each would need a name, if you were inclined to name such things.  In the
example above, if yellow flowered plants of subsp. coerulea were
discovered, they would need their own name ("forma lutea Clark, perhaps).

I think the conceptual problems folks are experiencing with this area
highlights just how silly it is to give names to individual variants that
do not have a discrete geographical or ecological range, i.e., that occur
sporadically within populations.

Thomas G. Lammers, Ph.D.

Assistant Professor and Curator of the Herbarium (OSH)
Department of Biology and Microbiology
University of Wisconsin Oshkosh
Oshkosh, Wisconsin 54901-8640 USA

e-mail:       lammers at uwosh.edu
phone:      920-424-7085
fax:           920-424-1101

Plant systematics; classification, nomenclature, evolution, and
biogeography of the Campanulaceae s. lat.
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