608 



ACERACEAE 



20A. Inflorescence corymbose, with a short axis; leaves and petioles pubescent; lobes of leaves acuminate with an obtuse tip. 



19. A. diabolicum 

 20B. Inflorescence a fascicle, without an axis and peduncle; leaves and petioles pubescent only while young; lobes of leaves acuminate. 



20. /i. pycnanthum 

 1 B. Leaves compound, 3 (-5) -foliolate. 

 2IA. Flowers fasciculate, terminal on the branches; young branches, underside of leaves, and inflorescence coarsely pilose; petioles 2-3 



cm. long 21. A. nik.oense 



21B. Flowers in slender racemes; leaves glabrous to pubescent; petioles 5-8 cm. long. 



22A. Leaflets 3, all alike; ovary glabrous or loosely pubescent; flowers 4-merous 22. A. cissifolium 



22B. Leaflets 3-5, the terminal one larger; ovary pubescent; flowers 5-merous 23. ^. negundo 



1. Acer sieboldianum Miq. A. japonicum var. sieboldi- cm. long, glabrous; flowers pale yellow, 6-8 mm. across; sepals 

 anum (Miq.) Fr. & Sav.; A. sieboldianum var. typicum Maxim. broadly lanceolate, about 4 mm. long; ovary with a few long 



Ko-HAucHiwA-KAEDE, Itaya-meigetso. Tree with the hairs; samaras glabrous, the wings ascending, about 2 cm. 



young branches, inflorescence, and petioles white-pubescent; long including the nutlets. May-June. Mountains; Hon- 



leaves chartaceous, rounded, 6-8 cm. wide, palmately 7- to 11- shu, Shikoku. 



lobed, sometimes to the middle, shallowly cordate to truncate 4. Acer palmatum Thunb. A. polymorphum Sieb. & 



at base, white-pubescent while young, later nearly glabrous, Zucc, non Spach; A. polymorphum var. palmatum (Thunb.) 



the lobes narrowly ovate to broadly lanceolate, acuminate, K. Koch; A. jormosum Carr.; A. palmatum var. thunbergii 



sharply toothed, the petioles 3-4 cm. long; inflorescence a Pax; A. eupalmatum Koidz.; A. palmatum var. quinquelobum. 



many-flowered compound pendulous corymb, the peduncles K. Koch; A. palmatum forma genuina Miq. Iroha-mo- 



3-5 cm. long; flowers small, pale yellow, 5-merous; sepals miji, Takao-kaede, Momiji. Tree, with the young buds 



about 3 mm. long, pubescent on the outside; ovary white- loosely yellowish brown pubescent, soon glabrous; leaves 



pubescent; samaras nearly glabrous, the wings ascending, chartaceous, suborbicular, 4-7 cm. wide, cordate-truncate or 



1.5-2 cm. long inclusive of the nutlets. May. Woods and subcordate at base, glabrous, palmately 5- to 7-lobed often to 



thickets in mountains; Hokkaido, Honshu, Shikoku, Kyushu; the middle, the lobes lanceolate to broadly so, acuminate, 



common. Many cultivars are grown in gardens. rather prominently duplicate-serrate, the petioles glabrous, 



Var. microphyllum Maxim. Hime-uchiwa-kaede. Leaves slender, 3-5 cm. long, reddish; inflorescence a glabrous, pendu- 



smaller. Occurs with the typical phase. lous, more than 10-flowered compound corymb, the slender 



2. Acer japonicum Thunb. A. monocarpon Nakai peduncles 3-4 cm. long; flowers dark red, 4-6 mm. across; 



Hauchiwa-kaede. Tree with glabrous branches; leaves sepals oblanceolate, about 3 mm. long, loosely brown-pubes- 



orbicular-cordate, 7-12 cm. wide, palmately 9-(7-ll)-lobed, cent at apex; ovary glabrous or with few rusty brown soft 



shallowly so, cordate at base, duplicate- or incised-toothed, with hairs; samaras glabrous, ascending or spreading, the wing 



long scattered white hairs while young, soon glabrate except about 1.5 cm. long. Apr.-May. Woods and thickets in 



for an axillary tuft beneath, the lobes narrowly ovate, acumi- lowlands and mountains; Honshu, Shikoku, Kyushu; very 



nate, the petioles 2-3.5 cm. long, pubescent while young; in- common and variable, with numerous cultivars grown in 



florescence corymbose, few-flowered, pendulous, white-pubes- gardens. Korea. 



cent while young; flowers 10-15 mm. across, 5-merous; sepals Var. amoenum (Carr.) Ohwi. A. amoenum. Carr.; A. 



elliptic or oblong, dark reddish purple; samaras pendulous, sanguineum var. amoenum. (Carr.) Koidz.; A. palmatum 



pubescent while young, often glabrate, the wings ascending, subsp. amoenum (Carr.) Hara; A. palmatum subsp. septem- 



2-2.5 cm. long inclusive of the nutlets. ^May. Woods and lobiim Koidz., excl. syn.; A. euseptemlobum Koidz. O-mo- 



thickets on mountains; Hokkaido, Honshu; rather common miji. Leaves larger, 6-10(-12) cm. wide, palmately 7(-9)- 



and frequenriy planted; many cultivars are grown in gardens. lobed, sometimes to the middle, the lobes rather regularly ser- 



Cv. Aconitifolium. A. japonicum forma aconitifolium rulate; wings of samara 2-2.5 cm. long inclusive of the nutlets. 



(Meehan) Rehd. A. japonicum var. aconitifolium Meehan; A. Apr.-May. Mountains; Hokkaido, Honshu, Shikoku, 



circumlobatum var. heyhachii (Matsum.) Makino; A. hey- Kyushu; very variable and frequently planted in gardens. 



hachii Matsum. ^Mai-kujaku. Leaves dissected almost to Forma latilobum (Koidz.) Ohwi. A. palmatum var. latilo- 



the base with deeply incised, rhombic-oblanceolate lobes. batum Koidz. Hiro-ha-momiji. Lobes of the leaves 



Var. insulare (Pax) Ohwi. A. circumlobatum Maxim.; broader, deltoid or deltoid-ovate. Western part of Honshu 



A. circumlobatum var. insulare Pax; A. japonicum var. circum- and Shikoku. 



lobatum (Maxim.) Koidz. O-meigetsu, Shinano-ha- Var. matsumurae (Koidz.) Makino. A. palmatum subsp. 



uchiwa. Wings of samaras horizontally spreading. Hon- matsumurae Koidz.; A. matsumurae (Koidz.) Koidz.; A. 



shu. ornatum var. matsumurae (Koidz.) Koidz. Yama-momiji. 



Var. kobakoense (Nakai) Hara. A. \obahoense Nakai Leaves 5-8(-10) cm. wide, 7(5-9)-lobed to the middle, the 



Kobako-hauchiwa. Leaf-lobes simply and coarsely lobes narrowly ovate to broadly lanceolate, prominently dupli- 



toothed. Hokkaido. cate- or incised-serrate; wings of samaras 15-25 mm. long in- 



3. Acer shirasawanum Koidz. O-itaya-meigetsu. Tree elusive of the nutlets. May. Mountains; Hokkaido, Hon- 



with glabrous branches; leaves chartaceous, orbicular, 6-10 shu, Shikoku, Kyushu; common and variable; many cultivars 



cm. wide, palmately 9- to 11-lobed, shallowly so, somewhat of this variety are grown in gardens. 



cordate at base, rather prominently duplicate-serrate, white- 5. Acer tenuifolium (Koidz.) Koidz. A. shirasawanum 



pubescent on both sides while young, soon glabrous except var. tenuifolium Koidz.; A. dissectum var. tenuifolium 



for an axillary tuft beneath, the lobes ovate, acuminate, the (Koidz.) Koidz. Hina-uchiwa-kaede. Tree with gla- 



petioles 3-8 cm. long, rather slender, glabrous; inflorescence a brous branches; leaves membranous-chartaceous, thin, ovate- 

 more than 10-flowered compound corymb, the peduncles 4-6 orbicular, 4-7 cm. wide, cordate at base, (5-) 7- to 9-lobed, 



