Toisusu cardiophylla (Trautvetter & Meyer) Kimura var. maximowiczii (Komarov) Kimura.

Trees to 20 m tall; trunk to 1 m d.b.h.; bark dull brownish gray. Branches slender; branchlets green or grayish green, yellowish in winter, glabrous. Buds ovoid, shiny. Stipules ovate-orbicular, dentate, caducous; petiole 0.5-1.8 cm; leaf blade ovate-oblong or ovate-lanceolate, ca. 12 × 3.4 cm, abaxially pale, glabrous, adaxially dark green, pubescent along veins, glabrescent, base ± obtuse, rarely cordate, margin serrate, apex long acuminate. Flowering coetaneous. Male catkin erect or

spreading, 2.5-4.5 cm, pedunculate, densely flowered; rachis glabrous; bracts obovate, 2-5 mm, ciliate, 3-5-veined. Male flower: glands 2; stamens 5, central 3 longer than lateral 2, 6-7 mm; filaments pubescent at base; anthers yellow. Female catkin pendulous, 4-6(-10) cm, loosely flowered, to 5-15 cm in fruit; bracts yellowish, oblong, abaxially pilose, apex acute, caducous. Female flower: adaxial glands 2, abaxial gland 1 or absent; ovary ovoid-lanceolate, glabrous, stipitate; style 2-lobed; stigma lanceolate, 2-parted; style and stigma caducous in fruit. Fl. May-Jun, fr. Jun-Jul.

Used for timber, matchwood, and as a nectariferous plant.

300-800 m. Heilongjiang, Jilin, Liaoning [Korea, Russia (Far East)].