Keys for the omnicient...

Timothy S. Ross rosst at CGS.EDU
Wed Sep 6 18:46:20 CDT 1995

        It is clear enough from the current discussion of dichotomous keys
that one person's "OK key" is another person's "hated key".  I offer a
couple of my "favorites" from the Southern California flora:

>From Camissonia (Onagraceae):

19.  Pollen 25-100 percent 4- or 5-pored.........C. robusta
19.  Pollen up to 5 percent 4-pored.
    20.  Capsule markedly quadrangular in transection.
         ........................................C. lewisii
    20.  Capsule not markedly quadrangular in transection,
         at least in living material.
         ...(6 additional spp with quadrangular capsules)...

>From the key to the subspecies of Argemone munita (Papaveraceae):
(the entire key is lengthy, so is severely abbreviated here)

A.  Stems with ca. 0-80 prickles per sq. cm. at 5 cm. below the
    oldest capsule; leaf surfaces smooth or sparingly prickly.
        ...(ssp. robusta, with ca. 0-10 prickles; ssp. munita,
           with ca. 10-20; and ssp. munita x ssp. rotundata,
           with ca. 50-80 prickles...)
A.  Stems with ca. 80-500 prickles per sq. cm. at 5 cm. below
    the oldest capsule; leaf surfaces moderately to closely
        ...(ssp. munita x ssp. rotundata, with ca. 80-180 prickles;
           ssp. rotundata, with ca. 120-500 prickles; and ssp.
           argentea, with ca. 100-300 prickles...)

In the additional leads to subspecies, the word "usually" is used
no less than eleven times.

        Sometimes it is easier to ask for a revelation from God than
it is to try and key out your plants with the "best" available key...

Sr. Curatorial Asst.
RSA-POM Herbarium
Rancho Santa Ana Botanic Garden
1500 North College Avenue
Claremont, CA 91711, U.S.A.
(909) 625-8767 ext. 233
FAX (909) 626-7670
rosst at

"At the end of a fortnight, I fired myself for willful incompetence."
              -- Donald Culross Peattie (The Road of a Naturalist, 1941)

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