台灣植物誌 第二版 Flora of Taiwan, 2nd edition Vol. 3
Six Species, tropical Asia to eastern Australia; one species in Taiwan.
1. Rhodomyrtus tomentosa (Ait.) Hassk., Fl. Beibl. 2: 35. 1842; Chang in Fl. Taiwan 3: 828. Pl. 830. 1979. 桃金孃 Pl.443
Myrtus tomentosa Ait., Hort. Kew 2: 159. 1789.
A small evergreen shrub, branches and inflorescences with a short soft tomentum. Leaves opposite, thickly coriaceous, ovate-elliptic, 5-7 cm long, 2-3.5 cm broad, obtuse at apex, obtuse to acute at base, 3-nerved, nerves reaching the apex of the blade, shining above, tomentose below; petioles about 4-6 mm long, tomentose. Flowers in short axillary cymes, large, rose-pink, about 2.5 cm across; calyx tomentose, lobes 5, subtended by 2 small bracts; bracts ovate; petals 5, elliptic, not tomentose, 12 mm long, stamens numerous. Berry elliptic, about 12 mm long, purplish when ripe, crowned with the persistent calyx. Seeds small, numerous.
India, Southern China through Malaysia to Australia. In Taiwan mainly in the northern part and on Lutao.
TAIPEI: Neihu, Kuoh 11496; Taipei, Sya s. n. 1927*, Chen s. n. 1962*. ILAN: Konishi 18081. TAITUNG: Lutao, Chang 4098.
4. SYZYGIUM Gaertner 赤楠屬
Evergreen trees or shrubs. Leaves opposite, coriaceous or membranaceous, penninerved. Flowers in racemes, cymes or panicles; calyx-tube globose or more or less elongated, lobes 4 or 5; petals 4 or 5; free or connate into a small hood (calyptra), mostly early caducous; stamens numerous, in 1 to numerous rows, occasionally united into 4 bundles, filaments filiform, anther sacs parallel and opening longitudinally; ovary 2-3-celled, styles filiform, stigma small; ovules numerous in each cell. Berry drupaceous, crowned with the persistent calyx-limb. Seeds few, globose or variously compressed; seedcoat loosely or closely adhering to the pericarp; embryo divided, i. e., with distinct cotyledons.
About 75 species in the Tropics of the Old World; about nine species in Taiwan.
KEY TO SPECIES
1. Flowers terminal.
2. Flowers large, 1.5-2 cm across; calyx-lobes conspicuous, 5 mm long, 8 mm broad… 9. S. tripinnatum
2. Flowers small, less than 8 mm across; calyx-margin truncate or only with short lobes.
3. Fruit globose.
4. Leaves 10-14 cm long… 5. S. kusukusense
4. Leaves less than 5 cm long.
5. Leaves with distinct veins, petioles about 1 cm long… 4. S. formosanum
5. Leaves with obscure veins, petioles 2-5 mm long… 1. S. buxifolium
3. Fruit elliptic, ovate or obovoid.
6. Fruit large, 1.2-1.5 cm across… 6. S. paucivenium
6. Fruit small, less than 1 cm across.
7. Pedicels stout with 2 broadly ovate bracts; leaves with distinct veins… 2. S. densinervium var. insulare
7. Pedicels slender only with minute bracts; leaves with obscure veins… 3. S. euphlebium
1. Flowers axillary.
8. Calyx-tube gradually attenuate to the base, about 2 cm long; fruit cylindric, about 2 cm long… 8. S. taiwanicum
8. Calyx-tube not as above, rather short; fruit globose, about 8 mm long… 7. S. simile