Oregon Flora Image Project
Erythranthe primuloides (Benth.) G.L. Nesom & N.S. Fraga primrose monkeyflower - native
Phrymaceae

Click on an image for a larger version. All images Gerald D. Carr unless otherwise noted.  See additional images of E. primuloides at other locations.

The images on this page are of two distinct forms of E. primuloides occurring in intimate contact in a small boggy area near the shore of Timpanogas Lake [S side of Timpanogas Lake at end of NFD Rd. 398, off FR 2154, SE of Oakridge, 5290 ft. elev., N43.41024, W122.11544, Douglas Co., OR, 7/16/2013].  Although the two forms are closely sympatric and commonly in physical contact at this site, no individuals were detected that appeared to be morphologically intermediate.  

Of the two forms, the smaller and generally shorter one has much smaller flowers (1/3 to 1/2 as wide as the larger form) that are only weakly two-lipped, and has leaves that are very conspicuously long-hirsute on the upper surfaces. Guy Nesom, who is preparing the treatment of the genus for the FNA project, has recently examined all of the specimens of this species in the OSC collection and considers this form to belong to the somewhat variable taxon, E. primuloides (including E. (M.) primuloides var. pilosellus (Greene) Smiley). 

According to Nesom (Pers. Comm.), the larger and generally taller form with essentially glabrous leaves and much larger and noticeably more strongly two-lipped flowers is currently not formally recognized.  Nesom considers its occurrence with "typical" E. primuloides without intermediate forms to be "highly perplexing."  It appears that most of the E. primuloides sites in Oregon support only one or the other of these two forms but both are found in intimate contact at Timpanogas Lake and a few other locations.  The ability of these two distinct forms to occur sympatrically without apparent production of morphologically intermediate individuals suggest that they are reproductively isolated in some way and therefore merit formal taxonomic recognition.  Chromosome numbers of n=9 and n=18 have been reported for E. primuloides and n=9 for E. pilosellus (now considered a synonym of the former species) at several locations in California.  If the two forms discussed here represent different ploidy levels they would be afforded some degree of isolation and a stronger case for formal recognition of the large-flowered form could be made.  However, chromosome numbers have not been determined for these forms at this site or elsewhere in Oregon.  

"typical" primuloides

Note weakly 2-lipped flowers

"typical" primuloides

Note very conspicuous long hairs on upper leaf surfaces

"typical" primuloides
  "typical" primuloides

Both varieties are capable of producing rhizomes and/or stolons

 
   
Large-flowered form (mostly)

Note larger stature and more prominently 2-lipped flowers.  A much smaller vegetative plant of "typical" primuloides with hairy leaves can be seen in the lower left corner of the image

Large-flowered form

Note robust plant with glabrous leaves and long peduncles

Large-flowered form

Flower in early anthesis

  Large-flowered form

Note strongly 2-lipped flower at late anthesis

Both forms in situ

Smaller plant with hairy leaves and nearly actinomorphic flower at anthesis in upper right of image is "typical" primuloides

 
   
Both forms in situ

Large-flowered form at upper right corner of image, "typical" primuloides below

Both forms ex situ

Large-flowered form on left, exhibiting shorter than average stem length; "typical" primuloides on right, exhibiting longer than average stem length and prominent stolon

Both forms in situ

Large-flowered form on left, "typical" primuloides on right

 


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