Betulaceae 



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6B. Leaves obovate-orbicular to nearly obcordate, truncate to cmarginate or truncate-rounded at apex, broadly cuncate at base, with- 

 out teeth on lower margin. 



7A. Leaves glaucous beneath 6. A. matsiimtirae 



7B. Leaves pale green and not glaucous beneath. 



8A. Leaves membranous, pale green beneath, irregularly undulate-toothed, with 6 or 7 pairs of weak lateral nerves, with axillary 

 tufts of brown hairs beneath; fruiting aments oblong or short-cylindric, 15-25 mm. long, 6-8 mm. in diameter. 



7. A. fauriei 

 8B. Leaves firm, pale brownish green beneath, the teeth minute, depressed mucronate, the lateral nerves of 7-9 pairs prominently 



raised beneath; fruiting aments ovate-ellipsoid, 1.5-2 cm. long, 8-12 mm. In diameter 8. A. semilatoides 



B. Leaves not plicate in bud, narrowly ovate, ovate-elliptic or narrowly oblong, acuminate, the lateral nerves more or less arcuate 

 above. 



9A. Leaves dull above, cuneate or acute at base, the lateral nerves of 7-9 pairs; petioles 1.5-3 cm. long 9. A. japonica 



93. Leaves smooth and slightly lustrous above, becoming reddish when dry especially on nerves, shallowly cordate, the lateral nerves 

 9-12 pairs, rather prominently raised beneath; petioles 1-1.5 cm. long 10. /f. Irabcctilosa 



1. Alnus sieboldiana Matsum. A. firma var. sieboldiana 



(Matsum.) Winkl. Oba-yashabushi. Large shrub or 



small tree with rather stout yellow-brown to gray-brown, gla- 

 brous branches; leaves ovate or narrowly so to deltoid-ovate, 

 6-10 cm. long, 3-6 cm. wide, appressed pilose on the nerves 

 beneath while young, gradually acute to short-acuminate, 

 rounded at base, doubly serrate with mucronate teeth, pale 

 green beneath, the lateral nerves of 12 to 15 pairs, the petioles 

 10-15 mm. long, glabrous; pistillate inflorescence with pedun- 

 cles 1-2 cm. long, pubescent while young, ascending to spread- 

 ing, rather thick; fruiting aments broadly ellipsoidal, 2-2.5 

 cm. long. Mar. Lowlands and foothills, especially abun- 

 dant near the sea; Honshu (Kanto Distr. and westw. to Kii 

 Prov.). 



2. Alnus firma Sieb. & Zucc. A.yashaMiXsura.-yA.firma 

 var. yasha (Matsum.) Winkl. — — Yashabushi. Much- 

 branched small tree or large shrub with gray-brown often 

 puberulous branchlets often scattered pilose while young; 

 leaves ovate or narrowly so to narrowly ovate-deltoid, 5-10 

 cm. long, 2.5-4.5 cm. wide, gradually acuminate, rounded at 

 base, mucronate-toothed, with a mucro between the teeth, the 

 nerves beneath with appressed hairs, glabrescent, the hairs 

 sometimes also on the upper side, the lateral nerves 13-17 

 pairs, the petioles 7-12 mm. long; staminate inflorescence from 

 the terminal and upper lateral buds; pistillate aments 1 or 2, 

 the peduncles pubescent while young, erect or ascending, 5-15 

 mm. long, the mature aments ovoid-ellipsoid, 15-20 mm. long. 

 Apr. Kyushu; common in mountains. 



Var. hirtella Fr. & Sav. A. hirtella (Fr. & Sav.) Koidz. 



MiYAMA-YASHABUSHi. Branches and leaves pubescent. 



Honshu; common. 



3. Alnus pendula Matsum. A. firma var. multinervis 



Kegel; A. multinervis (Kegel) Callier Hime-yashabushi. 



Much-branched small tree or large shrub with dark gray- 

 brown, slender, evanescent pilose branches; leaves narrowly 

 ovate to broadly lanceolate, long-acuminate, with short, mucro- 

 nate, double teeth, broadly cuneate at base, pale green and 

 appressed pilose on nerves beneath, with 20-26 pairs of lateral 

 nerves, the petioles pilose, 3-8 mm. long; staminate aments 

 from the terminal and upper lateral buds, the pistillate on the 

 lower part, 3-6 in a group, nodding or subpendulous; fruiting 



aments broadly ellipsoidal, about 15 mm. long. Apr. 



Mountains; Hokkaido, Honshu; common. e. Asia. 



4. Alnus maximowiczil Callier. A. viridis var. sibirica 

 sensu auct. Japon., non Kegel; A. sinuata var. \amtschatica 

 Callier; A. viridis subsp. maximowiczii (Callier) Hult. 

 Miyama-han-no-ki. Much-branched, large to small shrub 

 or small tree, with rather thick, gray-brown to dark gray gla- 

 brous to glabrescent branches; leaves broadly ovate to ovate- 



orbicular, 6-10 cm. long, 4-7 cm. wide, abrupdy short-acumi- 

 nate to short-acute, rounded to shallowly cordate at base, with 

 minute mucronate teeth, pale green and glabrous or nearly so 

 beneath except for axillary tufts of hairs, the lateral nerves of 

 10 to 12 pairs, the petioles glabrous, 1-3 cm. long; staminate 

 inflorescence from the terminal and upper lateral buds, the 

 pistillate aments 3-5 in a group, loosely racemose on a short 

 axis, arising from the buds below the staminate, the peduncles 

 ascending, the pistillate aments broadly ellipsoidal, 1-1.5 cm. 



long. June. High mountains, often ascending to the alpine 



zone; Hokkaido, Honshu (centr. and n. distr.) ; common and 



very variable. Kamchatka, Sakhalin, Kuriles, Ussuri, and 



Korea. 



5. Alnus hirsuta Turcz. A. incana var. hirsttta Spach; 



A. tinctoria Sarg.; A. sibirica var. hirsuta (Turcz.) Koidz. 



Ke-yama-han-no-ki. Tree with densely pubescent branch- 

 lets and inflorescence; leaves broadly ovate-orbicular to broadly 

 elliptic, 7-12 cm. long and as wide, obtuse to acute, sometimes 

 nearly rounded at apex, rounded to subtruncate at base, shal- 

 lowly pinnately incised, irregularly toodied, usually short- 

 pilose but often becoming glabrate above, densely pubescent 

 beneath, the lateral nerves of 6 to 8 pairs, the petioles 1.5-3 

 cm. long; staminate inflorescence with 2-A aments, borne from 

 the apical and upper lateral buds, die pistillate aments 3-5, 

 borne immediately below; fruiting aments ellipsoidal to ovate- 

 oblong, 15-25 mm. long. Apr. Mountains and hills; Hok- 

 kaido, Honshu, Shikoku, Kyushu; very variable. Sakhalin, 



Kamchatka, Korea, and e. Siberia. 



Var. sibirica (Fischer) C. K. Schn. A. sibirica Fisch.; A. 



incana var. sibirica Spach; A. incana var. glauca Kegel 



Yama-han-no-ki. With nearly glabrous parts; leaves promi- 

 nendy glaucous beneath; a common variant in our area, 

 occurring with dbe typical phase. 



6. Alnus matsumurae Callier. A. incana var. emargi- 



nata Matsum.; A. emarginaia (Matsum.) Shirai Yahazu- 



HAN-No-Ki. Small tree or rarely large shrub with dark 

 gray-purple glabrous branches; leaves obcordate-orbicular, 5-10 

 cm. long and as wide, glabrous or nearly so above, appressed- 

 pilose on the nerves beneath while young, gray-glaucous be- 

 neadi, rounded and distincdy emarginate, irregularly toothed, 

 broadly cuneate at base, the lateral nerves of 6 to 9 pairs, the 

 petioles glabrous, 1-3 cm. long, dark purple-brown when 

 dried; staminate aments solitary or paired, terminal and on 

 upper part of branches, the pistillate aments 2-5 in a group, 



the fruiting ones elliptic, 15-18 mm. long. May-June. 



High mountains; Honshu (centr. and n. distr.); rather com- 

 mon. 



7. Alnus fauriei L^v. A. glutinosa var. cylindrostachya 

 Winkl.; A. schncideri Callier; A. cylindrostachya (Winkl.) 



