Vitaceae

Dang, Viet Cuong, Lu, Limin, Nguyen, Van Hieu, Habib, Sadaf, Barrett, Russell L. & Chen, Zhiduan, 2016, A new record of the genus Yua (Vitaceae) from Vietnam, Phytotaxa 255 (3), pp. 274-280 : 279

Key to the genera of Vitaceae in Vietnam

1. Petals united at apex, shed as a cap-like calyptra; inflorescence a compact, paniculate thyrse; bark on older twigs usually loose, peeling off in stripes ...................................................................................................................................................................... Vitis

- Petals free; inflorescence a loose thyrse, panicle, dichasium, corymbose cyme, or umbel; bark intact, not peeling off in stripes ...2

2. Inflorescence a loose thyrse or panicle, base subtended by a tendril ............................................................................. Ampelocissus

- Inflorescence a loose dichasium, corymbose cyme, or umbel, base without tendrils ........................................................................3

3. Petals 5................................................................................................................................................................................................4

- Petals 4................................................................................................................................................................................................6

4. Tendrils 4–12-branched, tips usually with adhesive discs........................................................................................... Parthenocissus

- Tendrils usually 2(–3)-branched or unbranched, tips without adhesive discs....................................................................................5

5. Disk inconspicuous; inflorescence a compound dichasium, without reduced inflorescences appearing on tendrils..................... Yua

- Disk well developed, 5-lobed; inflorescence a corymbose cyme, reduced inflorescence often appearing at tips of tendrils.............. ........................................................................................................................................................................................... Ampelopsis

6. Inflorescence leaf-opposed; seeds with an encircling raphe near base; leaves simple.............................................................. Cissus

- Inflorescence usually axillary or pseudo-axillary, rarely leaf-opposed; seeds with 1 or 2 conspicuous ventral cavities nearly as long as seeds; leaves compound .................................................................................................................................................................7

7. Style conspicuous, stigma undivided, slightly expanded ...................................................................................................... Cayratia

- Style inconspicuous or short, stigma usually 4-divided, rarely irregularly divided.......................................................... Tetrastigma