Evolvulus oreophilus

Evolvulus oreophilus Greene

by Bob Harms email-here

[Click on image for enlargement.]

‘Type’ Specimens (at Missouri Botanical Garden; images adapted from those at Tropicos):

In 1905 E. L. Greene declared a new Evolvulus species E. oreophilus (Leaflets of Botanical Observation and Criticism. 1:151. 1905), the total description being:

Evolvulus oreophilus. Depressed and compact, the stems many from the subligneous branched crown of a thick tap-root, all floriferous from the base, densely leafy: leaves elliptic-oblong, sessile, acute, 1/2 inch long, canescent with a dense appressed silky pubescence: corollas purple, nearly 1/2 inch broad at full expansion, the pedicels very short, in fruit recurved. Dry hills west of Hillsboro, at 5,500 feet at base of Black Range, New Mexico, Aug. 1904, O. B. Metcalfe, n. 1228.

Greene's E. oreophilus has subsequently been treated variously as a synonym of:

E. nuttallianus — e.g., E.O. Wooton & P.C. Standley, Flora of New Mexico p. 516 (1915); D.F. Austin, Annotated checklist of Arizona Convolvulaceae, Sida 14:448 (1990)¹;
E. sericeus var. discolor — e.g., S.J. van Ooststroom, A monograph of the genus Evolvulus p. 134 (1934); I. L. Wiggins, Vegetation and Flora of the Sonoran Desert I p. 1140 (1964).

The collection 0. B. Mefcalfe 1228 is represented in numerous herbaria around the world, and only in Nov. 2012 was the collection at US declared as lectotype (by R.S. Felger et al., Convolulaceae of Sonora, Mexico. I). Noted by van Ooststroom were US, M (Berlin), NH (South Africa); by Austin: NMC, NY, UC, US. Images at JSTOR are from ILL, MO, NY, US, WIS (1228 on label crossed out and 27719 inserted, but date and location are the same, with notation ‘isotype’ apparently added in 1965 by L.H. Shinners); and Google search also turned up DAO (Canada). There is not one at Notre Dame University (NDG).

The two MO collections above are both labeled "Type Specimens", but only the one on the left is O.B. Metcalfe 1228 with the correct date and locality. The righthand specimen is clearly not type material. The specimen on the left is E. sericeus*; that on the right (2755547) is not — it is E. nuttallianus. (They do not show annotation beyond the determinations by Greene as E. oreophilus.) The righthand specimen may be one reason that some authors synonymize E. oreophilus with E. nuttallianus, but use of this specimen as type material is clearly in error.

Four Additional (‘type’) Specimens are also E. sericeus* (images adapted from those at JSTOR). The selections shown, especially in the enlarged versions, all 4 collections represent the same taxon. (For general discusion of differentiae.) The overall habit and the conduplicate falcate leaves are distinctive for E. sericeus. Closer examination of details (by examining these using JSTOR's Viewer) show that sepal form and leaf venation are also clear differentiae supporting the identification as E. sericeus. Compare the prominent midrib of E. nuttallianus leaves on the above top right specimen with leaves of the top left E. sericeus specimen, and with other herbarium specimens of E. nuttallianus at Tropicos.

I have now seen the NMC isotype specimens, and they provide very clear evidence to support the determination as E. sericeus.

Click on image for enlargement.

US [as determined by D.F. Austin]	NY [as determined by D.F. Austin; the note about van Ooststroom of unknown origin]

US [same sheet as above; as determined by S.J. van Ooststroom]	ILL [as determined by A.G. Jones]

WISC [as determined by L.H. Shinners]

* To simplify the presentation I have omitted ‘var. discolor’ and hold open the possibility that Greene's species may merit recognition.
¹ Austin notes:

Specimens that were separated as E. oreophilus Greene were treated by Ooststroom (1934) as E. sericeus var. discolor form B. These are better treated as E. nuttallianus because of their habit, corolla shape and color and indumentum on both leaf surfaces.

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