Nesom, G.L. 2012. Notes on £rythranthe orizabae (Phrymaceae). Phytoneuron 2012-43: 1-4. Published 16 May 2012. ISSN
2153 733X

NOTES ON ERYTHRANTHE ORIZABAE (PHRYMACEAE)

Guy L,. NESOM
2925 Hartwood Drive
Fort Worth, Texas 76109

ABSTRACT
Erythranthe orizabae (synonyms: Mimulus pachystylus, Mimulus orizabae) occurs from
Guatemala north in Mexico to Veracruz and Hidalgo. Its closest relatives are hypothesized to be a
group of six species of southeastern Asia, from Japan through China to the Himalayas. Typification
and a description of E. orizabae are provided and citation of representative specimens documents its
known geographic distribution.
KEY WORDS: Mimulus pachystylus, Mimulus orizabae, Erythranthe orizabae, Mexico

Suey of Mimulus in the broad sense, in preparation of the FNANM treatment and in

of ing segregate genera, has resulted in a better understanding of a species

endemic to Guatemala and southern Mexico. Minulus pachystylus, as treated by Grant (1924) and

generally recognized as such elsewhere (e.g., Standley & Williams 1973) proves to have an earlier
name and has been treated by Barker et al. (2012) within the genus Erythranthe Spach.

Erythranthe orizabae (Benth.) Nesom, Phytoneuron 2011-39: 41. 2012. Mimulus orizabae Benth.,
Prodr. (DC.) 10: 372. 1846. TYPE: MEXICO. [Veracruz, presumably:] "In monte Orizabae
Mexicanorum," April 1838, J. Linden 1092 (holotype: K digital image! photo-MO!).

Mimulus pachystylus AL. Grant, Ann. Missouri Bot. Gard. 11: 234. 1924. Type: MEXICO.
Chiapas. Cerro del Boqueron, Aug 1913, CA. Purpus 7015 (holotype: MO!; isotypes: BM, F
digital image!, UC, US digital image!).

Perennial, rhizomatous and rooting at the nodes. Stems prostrate, 10-30 cm, mostly simple,
lignescent. Stems and pedicels arachnoid-villous with multicellular hairs with colored crosswalls,
eglandular. Leaves: basal not persistent; blades ovate to broadly ovate, 10-30 mm x 5—20 mm,
venation suprabasal-acrodromous (pinnate) with slight tendency to appear brochidodromous (Fig. 3),
glabrous on both surfaces or coarsely pilose abaxially along veins, eglandular, margins coarsely
dentate to serrate, apex acute to obtuse, base rounded, petioles 3-9 mm. Calyces in flower 9-12 mm
and campanulate, in fruit 12-16 mm and cylindric-campanulate, weakly inflated, crinkly villous on
the angles with long hairs with colored crosswalls, lobes subequal, erect, convex to deltate-subulate or
nearly obsolete and represented only by a mucro, the calyx apex then nearly truncate except for the
slightly longer upper lobe. Fruiting pedicels 10—20(-60) mm. Corollas yellow, with 2 lines of red
dots along the bottom of the tube, tube cylindric-funnelform, 12-16 mm, strongly bilabiate and
sagittally compressed, throats open, ventral ridges eal Anthers included, glabrous. Capsule
included, narrowly elliptic-ovoid, 7-9 mm; tation axile. Cl number not reported.

Flowering Mar—Aug. Cloud forest, oak woods; 1700. 3100 m; Guatemala, Mexico (Chiapas,
Hidalgo, Oaxaca, Veracruz).

R tati Hecti GUATEMALA. Mpio. San Mateo Ixatatan, cloud forest near
the place called Kurus Lemun, 4 mi E of San Mateo Ixatataén along road to Barillas, 8500 ft, 7 Aug
1965, Breedlove 11642 (MO); [Depto. Escuintla,] Santa Rosa, near Escuintla, in virgin forest, 1600
m, 20 Jun 1941, Matuda 4246 (LL, MO). MEXICO. Chiapas. Mpio. San Cristobal las Casas, steep
NE slope of Zonehuitz, heavily wooded, 9300 ft, 11 Jul 1966, Breedlove 14525 (MO); [Mpio.
Siltepec,] [Santa Isabel Zijan] Fraylesca, near Siltepec, 11 Mar 1945, Matuda 5234 (LL-2 sheets);

Nesom: Notes on &rythranthe orizabae 2

pot line

ADELE LEWIS @RANT.

No,

“wa

Figure 1. Isotype collection of Mimulus pachystylus A.L. Grant (US).

Nesom: Notes on Enthrantte orizabae 3

Figure 2. Leaf of Zrythranthe orizabae (from US isotype of Mimulus pachystylus shown in Fig, 1).

Cerro del Boqueron, Aug 1913, Purpus 70/5 (UC). Hidalgo. Mpio. de Tenango de Doria, 10 km al
W de Tenango de Doria, bosque de encinos, ailes y Liguidambar principalmente, 1700-1800 m, 10
May 1980, Hemdndez Magafia and Hemdndez V. 431 (MO). Oaxaca. Mpio. San Felipe Usila,
cuenca del Rio Perfume (ladera), 7.5 km en linea recta al $ de Santa Cruz Tepetotutla, en un arroyo,
bosque meséfilo de montafia, 2230 m, 3 Apr 1994, Gallardo H. et al, 1044 (MO).

Grant (1924) included a brief description of Mimulus orizabae, essentially translated from
Bentham’s protologue, and placed it among a group of "doubtful and little-known species." Her
description of Mimulus pachystylus was much fuller. She knew the species only from Chiapas but
collections are recorded here from Guatemala, Chiapas, Oaxaca, Puebla, Veracruz (whence the type
of Mimulus orizabae), and Hidalgo. No species of Mimulus, however, has apparently been previously
included in accounts of the Veracruz flora (see comments by Durin-Espinosa 2006), nor was
Mimulus orizabae reported by Rodriguez J. (2001) for the Valley of Mexico.

The generic placement of Zrythranthe orizabae is indicated by its parietal placentation,
relatively long pedicels, and suprabasal-acrodromous leaf venation. As a species, it is characterized
by herbaceous, prostrate stems rooting at the nodes, young stems and adaxial leaf surfaces arachnoid-
villous with long, viscid, crinkly hairs sometimes with colored cross walls, leaves petiolate with ovate,
pinnately veined, serrate-margined blades, sometimes bicolored with a lighter abaxial surface, and
yellow, bilabiate and strongly sagittally compressed corollas with an open throat.

Nesom: Notes on rythranthe orizabae 4.

Erythranthe orizabae is superficially similar to . moschata (Douglas ex Lindl.) Nesom,
which has prostrate to ascending stems and petiolate leaves, but the latter occurs in the northern USA
and Canada and E. moschata and its closest relatives (Erythranthe sect. Mimulosma, Nesom 2011) are
characterized by a vestiture that includes stipitate-glandular hairs. The closest evolutionary
relationship of E. orizabae is hypothesized here to be with a group of apes outcewiee similar to sect.
Mimulosma but mostly without glandular hairs and with more f
venation — Erythranthe sect. Mimulasia (see Barker et al. 2012), species es of aay er Asia
from Japan through China to the Himalayas but also including E£. dentata (Nutt. ex Benth.) Nesom of
the Pacific Northwest.

ACKNOWLEDGEMENTS
Many thanks to the staff of MO, TEX, and UC-JEPS for help with herbarium and library
studies there. This study was supported in part by the Flora of North America Association.

LITERATURE CITED
Barker, W.R., P.M. Beardsley, N.S. Fraga, and G.L. Nesom. 2012. A taxonomic conspectus of
Phrymaceae: A narrowed circumscription for Mimulus, new and resurrected genera, and new

names and binati Phyt 2012-39: 1-60.

Duran-Espinosa, C. 2006. Scrophulariaceae. Flora of Veracruz 139: 1-47.

Grant, A.L. 1924. A monograph of the genus Mimulus. Ann. Missouri Bot. Gard. 11: 99-388.

Nesom, G.L. 2012. Taxonomy of Erythranthe sect. Mimulosma (Phrymaceae). Phytoneuron 2012-

41: 1-36.

Rodriguez Jiménez, C. 2001. Scrophulariaceae. Pp. 674-699, in Rzedowski, G.C. de, J. Rzedowski,
y colat 1 Flora F Amica del Valle de México (ed. 2). Instituto de Ecologia, A.C. y
Comisién Nacional para el Conocimiento y Uso de la Biodiversidad, Patzcuaro, Michoacan.

Standley, P.C. and L.O. Williams. 1973. Scrophulariaceae. Flora of Guatemala. Fieldiana, Bot.

24(9): 319-416.