Japanese Horse Chestnut

Aesculus turbinata is cultivated as an ornamental and for its timber. It has been confused in China with A. chinensis, but it differs in several characters, including its sessile (vs. petiolulate) leaflets, crenulate (vs. serrulate) leaflet margin, conic or cylindric-conic (vs. cylindric) thyrse, and verrucose (vs. dotted but smooth) capsule.

Trees to 30 m tall, to 2 m d.b.h. Branchlets pubescent when young. Petiole 7.5-25 cm, glabrous or pubescent; leaf blade 5-7-foliolate; leaflets sessile, abaxially slightly glaucous, oblanceolate, 15-35 × 5-15 cm, abaxially glabrous except villous in axils of lateral veins, or pubescent and more densely so on veins, base cuneate, margin shallowly crenate with crenations crenulate, apex abruptly acuminate; lateral veins in 18-26 pairs. Inflorescence glabrous or pubescent; peduncle 2-4 cm; thyrse conic or cylindric-conic, 12-25(-45) cm, 6-11 cm wide at base; branches up to 5 cm, 5-10-flowered; pedicels 3-4 mm. Calyx 3-5 mm, abaxially pubescent. Petals 4(or 5), white or pale yellow, with red spots and a yellow (later red) claw, unequal, 2 oblong and 2 oblong-obovate, 7-11 × 3-7 mm, abaxially pubescent. Stamens 6-10, 10-18 mm; filament sparsely villous; anther 1-1.5 mm. Style tomentose, sparsely so
near apex. Capsule dark brown, broadly obovoid or pyriform, 2.5-5 cm in diam., verrucose; verrucae low, suborbicular, unequal, 0.5-2 mm in diam.; pericarp 3-6 mm thick after drying. Seed usually 1, reddish brown, ± globose, 2-3 cm; hilum pale brown, occupying ca. 1/2 of seed. Fl. May-Jul, fr. Sep. 2n = 40.

Shandong (Qingdao), Shanghai [native to Japan].

Introduced to China, cultivated in parks; 100-200 m.

Aesculus turbinata f. pubescens (Rehder) Ohwi ex Yas. Endo; A. turbinata var. pubescens Rehder.

Aesculus turbinata, common name Japanese horse-chestnut (Tochinoki or Tochi (トチノキ（栃の木） or トチ（栃、橡）)), is native to Japan but cultivated elsewhere. It is a tree up to 30 m (98 ft) tall. Flowers are white to pale yellowish with red spots. Capsules are dark brown, obovoid to pyriform. The seeds were traditionally eaten, after leaching, by the Jōmon people of Japan over about four millennia, until 300 AD. Today the seeds are used in Japanese cuisine to prepare "Tochimochi".