262 WILSON EXPEDITION TO CHINA 
lata, caudata, lobulato-duplicato-crenata, dentibus sat angustis, obtusis cuspidatis, 
glandula capitata terminatis, supra accumbenti-villosa, subtus in nervis densissime, 
inter nervos laxius longe hirto-villosa, nervis utrinsecus 8-10. Involucrum circa 6 
mm. longum; pedunculus nullus; flores 1-2 umbellati, coaetanei foliis simul ad 
4 cm. longis; bractea semiexserta; pedicelli 12-22 mm. longi, laxe hirto-villosi; 
cupula 8 mm. longa, crasse tubulosa, in nervis parce pilosa, purpurea; sepala 
ovata, 4.5-4.5 mm. longa, minutissime parce serrulata, extus parce pilosa, intense 
purpurea; petala nulla!; stamina 26, ad 4 mm. longa; stylus staminibus 5 mm, 
longior, basi pilis longis paucissimis obsitus. 
Japan: In the Herbarium at Leyden are two sheets, on both P. apetala is 
mixed with P. incisa Thunberg; the labels can not be referred with certainty to 
either of the two species. 
A foliiferous branch kindly sent me by Matsumura as P. apetala seems to belong 
here: 
Ramus glaber, fuscus; gemmae 4 mm. longae, glabrae. Petioli 6-13 mm. longi; 
lamina obovata ad obovato-oblonga, 4-8.5 em. longa, 2-4 cm. lata, dentibus pri- 
mariis pro parte ad 7 mm. longis, supra pilis conspersa, subtus in costa nervisque 
hirto-villosa ceterum glabra v. subglabra, nervis utrinsecus 5-7. Cetera ut in 
specimine anthentico. 
Hokkaido: July 1906, H. Shirasawa. 
The species is really apetalous; but the calyx and sepals are colored intensely 
purple. lt was not respresented in any of the other collections I have consulted. 
Ser. 5. AMBLYODON, n. ser. 
98. Prunus gracilifolia Koehne. See p. 223. 
99. Prunus Rossiana Koehne. See p. 223. 
Grex II. MICROCERASUS (Spach, Roemer) Koehne, n. divis. 
Cerasus sect. Microcerasus Spach, Hist. Vég. I. 423 (1834); in Ann. Sci. Nat. 
sér. 2, XIX. 125 (sensu ampl.) (1843). 
Microcerasus Webb, Phytogr. Canar. II. 19 (sensu ampl.) (1836-40) — Roemer, 
Syn. Pl. III. 5, 93 (emend.) (1847). 
Sect. l. SPIRAEOPSIS Koehne, Deutsche Dendr. 306 (1893), sed excludenda 
“Prunus Simonii Carriére" et “P. triflora Roxburgh?” 
Subsect. 1. MYRICOCERASUS Koehne, n. subsect. 
100. Prunus pumila Linnaeus. Eastern North America. 
101. Prunus Besseyi Bailey. Eastern North America, 
Subsect. 2. SPIRAEOCERASUS Koehne, n. subsect. 
102. P. dictyoneura Diels in Bot. Jahrb. XXXVI, Beibl. 82, 57 (1905). 
Shensi: Tai-pei-shan, 1910, Wm. Purdom (No. 2); Yenan Fu, 1910, Wm. Pure 
dom (No. 344). Also collected in northern Shensi by G. Giraldi: Khin-lin-shan, 
May to June, 1894, (No. 1696); Mt. Caa-cun, July 30, 1892 (No. 1134); San- 
juen-shen, July 1893 (No. 1135); Po-uo-li, southwest of Tshin-z-shien (No. 5195). 
103. Prunus humilis Bunge in Mém. Étr. Acad. Sci. St. Pétersbourg, II. 97 (Enum. 
Pl. Chin. Bor.) (1833). — Hooker f. in Bot. Mag. CXX. t. 7335 (1894). — Koehne 
in Mitt. Deutsch. Dendr. Ges. XVIII. 181, fig. 3 (1909). 
