Paraconcavistylon wehrii (Manchester, Pigg et DeVore) Manchester et Judd in Manchester, Kvaček & Judd

Plant Fossil Names Registry Number: PFN001084


Authors: S. R. Manchester & W. S. Judd

Rank: species

Basionym: Concavistylon wehrii Manchester, Pigg et DeVore in Manchester, Pigg, Kvaček, DeVore & Dillhoff

Genus: Paraconcavistylon Manchester et Judd in Manchester, Kvaček & Judd

Reference: Manchester, S. R., Kvaček, Z. & Judd, W. S. (2020): Morphology, anatomy, phylogeny and distribution of fossil and extant Trochodendraceae in the Northern Hemisphere. – Botanical Journal of the Linnean Society 195(online): 467–484.


Holotype UWBM PB 101336, Burke Museum of Natural History and Culture, University of Washington, Seattle, Washington, USA
Figures: figs 1A–1E, 2A, 4A

Note: Holotype: Specimen bearing bot hinfructescence and leaves, collected and donated by Dwyane Day in August 1999.

Paratype: Isolated infructescence from Republic. USNM 537360 from USGS locality 2871, collected by Henry Landis in 1901. Previously figured as Trochodendron sp. (fig. 2; fig. 58 in Manchester et al. 2009)

Original diagnosis/description

Infructescence a raceme; axillary on vegetative stem; inflorescence axis 3 mm thick at base, narrowing to less than 1 mm distally. Fruits capsular, 5–7 mm wide, 5–6 mm high; pedicels short, 0.5 mm thick, 3–5 mm long, curved uniformly toward infructescence apex. Styles persistent, 4, 5, or 6 (variable); 1.9–2.9 mm long, arising subequatorially, curving toward the fruit apex; elliptical bulge (interpreted as nectary) beneath each style. Capsules smooth, with a basal thickening and whorl of perianth scars at junction with pedicel. Dehiscence apical, with separation initiating immediately above each style and joining apically to forma 4-, 5-, or 6-rayed starlike opening.
Twig bearing simple leaves in alternate phyllotaxy. Terminal bud 1 cm long, 5 mm wide, elongate, pointed apically; axillary bud 8 mm long, 1.8 mm wide; terminal bud scale scars 5–8, prominent, encircling stem. Petiole 8–12 mm long, nonpulvinate, short in relation to lamina length (9%–11%). Lamina obovate, 10.2–12.5 cm long × 3.1–3.5 cm wide; margin serrate with regularly spaced rounded, glandular, teeth. Venation pinnate with a straight midvein and 8–15 pairs of brochidodromous secondary veins. Intersecondary veins absent. Tertiary and higher-order veins forming an irregular mesh. Adaxial cuticle smooth, cells polygonal, anticlinal walls straight to slightly curved, almost equally sized, 30–45 μm in diameter. Abaxial cuticle showing unspecialized cells, straight-walled, stomatal complexes rounded-oval, 35–40 × 40–50 μm in diameter, stomatal ledges thick, bordering the broadly oval aperture and not reaching to the poles. Trichome bases lacking on both abaxial and adaxial cuticles.


The species name recognizes Wesley (“Wes”) Wehr (1929–2004), whose enthusiasm and generosity inspired this work.


Paleogene, Eocene
Tom Thumb Ash Member of the Klondike Mountain Formation, latest early Eocene


United States
Boot Hill, Republic, Ferry County, Washington; UWBM locality B4131

Plant fossil remain

macro- and meso-fossils-embryophytes except wood


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