Monarda humilis (Lamiaceae), a New Combination for a Species
from New Mexico, and a Key to the Species of Section Cheilyctis

                             L. Alan Prather and Jessie A. Keith
  Plant Biology, Michigan State University, East Lansing. Michigan 48824-1312, U.S.A.
                              alan@msu.edu; keithjes@msu.edu


ABSTrCT'r. A new combination. Monurda humilis,
is established to accommodate one of the two spe-
cies of Monarda sect. Cheilyctis that is found in
New Mexico. This species differs from tie other
species in New Mexico, M. .punctata, by its corolla
pigmentation, leaf size, and more diminutive and
gracile habit. A key to the six species of section
Cheilyctis is provided, and evidence for specific sta-
tus of several taxa is discussed.
   Key words: Lamniaceae, Monarda, New Mexico.
North America.


   A study of Monarda I.. specimens in the Uni-
versity of New Mexico tlerbarium (UNM) in August
2001 revealed two morphologically distinct species
of section Cheilyctis in New Mexico. They differ in
several characters (see below), but the most con-
spicuous differences are that one has small leaves
(2-4(5) cm long), corollas with the lower lip having
deep purple spots and deep purple margins on a
white background. purple upper lips. and purple
bracts. The other has large leaves (4-7 cm long),
corollas with a lower lip having purple or maroon
spots and margins and backgrounds that are white
or pale yellow in color, white or pale yellow upper
lips, and white bracts.
   The specimens of the large-leaved species are
from eastern and southern New Mexico and are as-
signable to M. punclata I.. Their large leaves, white
or pale yellow corollas, white bracts, and broadly
deltoid calyx teeth suggest they are best placed in
variety occidentalis (Epling) E. J. Palmer & Stev-
ermark (Scora. 1967). This variety is common in
adjacent areas of western Texas and Oklahoma.
   The specimens of the small-leaved species are
from central and western New Mexico. There are
no names available at the specific rank for the sec-
ond taxon. However. Torrey (1853) described M.
ipnctata var. humilis from a specimen collected
within he disriin e is of the small-leaved species.
He noted in the protologue that it may be a distinct
species. The English description is very brief, and
there is no Iatin diagnosis. but the description is
consistent with the small-leaved species. No sub-

NovoN 13: 104-109. 2003.


sequent workers took up Torrey's name. The type
of M. Ipnctata var. humilis is fragmentary and has
suffered some insect damage. but close examination
of the features of the stem, leaves, and calyx de-
termined that it is conspecific with the specimens
of the small-leaved species. We therefore elevate
Torrey's variety humilis to species rank by making
the new combination below and provide a descrip-
tion of the taxon. We also provide a key to the spe-
cies of section Cheilyctis andl briefly discuss the
taxonomy of the section. In particular we review
evidence for specific status of M. fruticulosa Epling,
M. maritima (Cory) Correll, M. starfieldii Small,
and M. riridissima Correll.


Monarda humilis (Torrev) Prather & J. A. Keith,
     comb. et stat. nov. Basionym: Monarda punc-
     tata var. humilis Torrey. Report of an Expe-
     dition down to the Zuni and Colorado Rivers
     166. 1853. TYPE: U.S.A. New Mexico: no
     date, /S. W.I Woodhouse s.n. (holotype, (;I).
     Figure 1.

   Annual herb. rarely branched at the base. usu-
ally branched above, 15-40(50) cm tall. Stems
slendrer often pigmented pink or purple, especially
at the base, covered in minute, unicellular, conical,
downcurved trihlomles. Leaves petiolate. blades
0.3-0.7 cm widle. 2-1(5) em long, elliptical to lan-
ceolate. usually entire, occasionally sparsely ser-
rate, covered in minute, unicellular, conical tri-
chlmes. Inflorescence of several verticillastrate
inflorescences in axillary positions along each flow-
ering stem. Bracts lanceolate to deltate. usually
purple on their alaxial surface, usually green on
the abaxial surface. Calyx tube 4-6 mm long. with
tiny unicellular trichomes scattered along the veins
on the outside of the tube, andl a ring of long, munl-
ticellular trichomres on the internal surface of the
apex of the tube. lobes ca. I tnm long, deltate. long-
ciliate, cilia  of  multicellular  trichomes. Corolla
0.7-1.5 c m long, lower lip with deep purple spots
and a deep purple targin on a white background.
upper lip purple, with short hairs and sometimes a