Acer sect. Rubra Pax, Bot. Jahrb. Syst. 6: 326. 1885.

Harris, AJ, Chen, Yousheng, Olsen, Richard T., Lutz, Sue & Wen, Jun, 2017, On merging Acer sections Rubra and Hyptiocarpa: Molecular and morphological evidence, PhytoKeys 86, pp. 9-42 : 26-27

publication ID	https://dx.doi.org/10.3897/phytokeys.86.13532
persistent identifier	https://treatment.plazi.org/id/7A3E1E90-B726-52FE-9FFA-D044942775E4
treatment provided by	PhytoKeys by Pensoft
scientific name	Acer sect. Rubra Pax, Bot. Jahrb. Syst. 6: 326. 1885.
status

Treatment

Acer sect. Hyptiocarpa W.P. Fang, Acta Phytotax. Sin. 11: 172. 1966.

Acer sect. Laurina Ogata, Bull. Tokyo Univ. Forests 63: 151. 1967.#

Type species.

Acer rubrum Linnaeus.

Description.

Trees, deciduous or evergreen, with labile sex expression ranging from monoecy to dioecy (possibly exclusively dioecious in A. pycnanthum ). Wood distinctly ring-porous, rays 1-4(10) cells wide. Bud scales imbricate, decussate, in pairs of 4-11. Leaves entire, unlobed, or 3- or 5- lobed, elliptic to ovate, toothed or entire, glaucous to blue-colored beneath; cuticular waxes of leaves comprising a smooth layer on the adaxial surface and bearing membranous platelets and wax splatter features abaxially; primary veins 1 or 3, 5 in 5-lobed individuals of A. saccharinum ; petioles sometimes turning red (e.g., new growth, late season). Inflorescences axillary (rarely terminal) from leafless buds, usually emerging before leaves, paniculate thyrses, racemes, or umbels. Sepals 5. Petals 0 or 5, red, red-green, or green when present. Stamens 5-12, inserted on ( A. laurinum and A. pinnatinervium ) or outside of staminal disk, disk sometimes reduced or absent ( A. rubrum , A. saccharinum , A. pycnanthum ). Carpels 2. Fruits schizocarps with partially inflated seed locules, sometimes turning red during maturation, partitioning wall generally narrower than the seed locules; mericarps diverging from each other at less than 90°, wings straight to slightly convex on the proximal (vein-dense) side, curved on the distal side. Some fruits seedless and partially developed at maturity.

Five species showing a disjunct distribution between eastern and southeastern Asia (3 spp.) and eastern North America (2 spp.), a common biogeographic pattern among Northern Hemisphere plant groups ( Donoghue and Smith 2004; Harris et al. 2013, 2017; Li 1952; Wen 1999, 2001; Xiang et al. 2015).

Acer laurinum Hasskarl, Tijdschr. Natuurl. Gesch. Physiol. 10: 138. 1843.

Acer javanicum Junghuhn, 1841

Acer niveum Blume, 1847

Acer cassiifolium Blume, 1847 (as cassiaefolium)

Acer philippinum Merrill, 1906

Acer garrettii Craib, 1920

Acer decandrum Merrill, 1932

Acer chionophyllum Merrill, 1941

Acer longicarpum Hu & W. C. Cheng, 1948

Acer macropterum T. Z. Hsu & H. Sun, 1997

Acer pinnatinervium Merrill, Brittonia 4: 109. 1941.

Acer machilifolium Hu & Cheng, 1948