Artocarpus tonkinensis A. Chev.

The wood is very hard and the fruit are edible.

Trees 14-16 m tall. Bark brown, coarse. Branchlets pale reddish brown, 1.5-2.5 mm thick, curly to appressed puberulent. Stipules pyramidal, often caducous and leaving a scar. Petiole 4-10 mm, sparsely pubescent; leaf blade elliptic, obovate, or narrowly oblong, 8-20(or longer) × 4-10 cm, leathery, abaxially greenish, densely pubescent and sparsely covered with short curly hairs along midvein, adaxially glabrous, base cuneate to rounded, margin entire or sometimes apically with a few shallow teeth, apex mucronate; midvein and secondary veins abaxially conspicuously raised and reddish when dry, secondary veins 6-9 on each side of midvein, tertiary veins pale brown. Inflorescences axillary, solitary. Male inflorescences obovoid to ellipsoid, 1-1.5 × 0.8 -1.5 cm; peduncle shorter than inflorescence; bracts petiolate, shield-shaped. Female inflorescences globose; bracts shield-shaped. Male flowers: calyx lobes 2 or 3, margin ciliate; anther ellipsoid. Female flowers: calyx completely connate; style exserted. Fruiting syncarp yellow when mature, reddish brown when dry, ± globose, ca. 6.5 cm in diam.; peduncle 3-4 cm. Drupes ellipsoid, 1.2-1.5 × 0.9-1.2 cm. Fl. summer to autumn.

Fujian, Guangdong, Guangxi, Guizhou, Hainan, S Yunnan [Cambodia, N Vietnam].

Sunny mountain slopes; below ca. 800 m.

Đối với các định nghĩa khác, xem Chay (định hướng).

Chay Bắc Bộ, còn gọi là chay vỏ tía hay chay Bắc (danh pháp hai phần: Artocarpus tonkinensis) là một loại cây gỗ mọc ở miền Bắc Việt Nam, nhất là các tỉnh miền núi trung du và thượng du. Ở miền xuôi cũng có trồng.