Platanus raynoldsii

Overview

Platanus raynoldsii is a fossil plant whose leaves consist of three leaflets. Research groups it under the name Platanites raynoldsii. Look for the three-part connection within a single leaf.^[1]

Key facts

The terminal and lateral leaflets have different vein arrangements. Three main veins spread through the terminal leaflet, while the lateral leaflets have pinnate venation. Smaller veins lead to teeth along the margins.^[1]

Time and place

The study lists material from Paleocene Danian localities and an Eocene Bartonian locality. It is known from different North American fossil sites, including present-day Montana and Oregon in the USA and Saskatchewan in Canada.^[1]

The time range describes source context, not the complete duration of this species.

Size, form and skeleton

The terminal leaflet is egg-shaped to elliptical and shallowly three-lobed. The lateral leaflets are opposite or nearly opposite, with unlobed, asymmetric blades.^[1]

Platanus raynoldsii had compound leaves made up of three leaflets. In Eocene fossils from Oregon, USA, the terminal leaflet was 8–12 cm long and 8–10 cm wide. Its broad blade and toothed margin help evoke the leaves of an ancient forest.^[7]

Habitat and reproduction

Follow the connection of the three leaflets from the swollen petiole base. Each leaflet also has a short stalk. The difference between isolated blades and an attached compound leaf becomes apparent.^[1]

Fossil discovery

The name traces back to Platanus raynoldsii, used by Newberry in 1868. The study lists USNM 7000 as the type specimen. The first part of the name changed according to the genus in which the fossil was placed.^[1]

References

1. Study of compound-leaved Platanaceae from North America
2. Study of compound-leaved Platanaceae from North America
3. Wolfe & Wehr (1987) — USGS Bulletin 1597 · Species description of Macginitiea gracilis
4. Burke Museum — Republic Macginitiea gracilis leaf
5. Manchester 2014 — Revisions to Roland Brown’s North American Paleocene flora
6. Pigg et al. 2023 — The early Eocene flora of Horsefly, British Columbia
7. Nares·Huegele·Manchester (2025) — Compound leaves of Eocene Platanaceae from North America

Research questions

The sinuses between the marginal teeth are rounded. Comparing teeth and veins alongside lobing adds more observation points for distinguishing similar fossil leaves.^[1]

Observation

The illustration represents one compound leaf composed of three connected leaflets. Follow the swollen petiole base to the terminal leaflet and examine differences between the lateral and central blades.^[1]