ROSACEAE. — SPIRAEA 445 
Spiraea hirsuta is very near S. chinensis Maximowicz, but that species is chiefly 
distinguished by the green, not glaucescent, more densely and yellowish pubescent 
lower surface of the leaves and their sharper and closer serration with acute teeth. 
The difference in the color of the pubescence is only well marked on leaves of the 
vigorous leafy shoots, and is often scarcely noticeable on those of flowering shoots. 
Spiraea hirsuta, var. rotundifolia Rehder, n. comb. 
Spiraea Blumei, var. rotundifolia Hemsley in Jour. Linn, Soc. XXIII. 224 
(1887). 
Spiraea Mazimowicziana Schneider, Ill. Handb. Laubholzk. I. 461 (1905). 
Western Hupeh: Changlo Hsien, thickets, side of streams, alt. 
600-1000 m., May 1907 (No. 2770); without precise locality, A. Henry 
(No. 3570, 3506*). 
Wilson's No. 2770 and Henry’s No. 3570 differ from No. 3506* which seems to be 
the type of this variety, in the leaves being crenately serrate from below the middle. 
Henry's No. 3506 in the Arnold Arboretum Herbarium belongs to S. hirsuta, 
although Schneider quotes this number as the type of his S. Maximowicziana. 
Spiraea tortuosa Rehder, n. sp. 
Frutex metralis ramulis angulatim flexis; ramuli hornotini albido- 
tomentosi, hornotini rubro-brunnei; gemmae parvae, perulis paucis 
glabrescentibus brunneis obtectae. Folia decidua, late ovalia v. fere 
suborbicularia, basi et apice rotundata, supra medium sparse inciso- 
crenato-serrata, v. subduplicato-serrata dentibus obtusiusculis utrin- 
que 2-3, 1-1.5 cm. longa et 9-12 mm. lata, supra cinereo-viridia, dense 
villosula, subtus albido-villoso-tomentosa, nervis rectis utrinque 2-3; 
petioli tomentosi, 1-3 mm. longi. Inflorescentia subumbellata, 5-12- 
flora, brevissime pedunculata, 1.5-2 cm. diam., in apice ramulorum 
paucifoliatorum, circiter 0.5 mm. longorum; pedicelli circiter 0.5 mm. 
longi, ut calyx villoso-tomentosi; flores 7 mm. diam., albi; sepala ovato- 
triangularia, extus villosa, intus glabra; petala suborbicularia, 3 mm. 
diam.; stamina 20, petalis triente breviora; discus conspicuus, lobatus, 
purpureo-brunneus, lobi distincti cum staminibus interioribus alter- 
nantia, dorso canalieulati staminibus seriei exterioris canaliculo 
adpressis; carpidia villosa; styli staminibus dimidio breviores. Fructus 
maturus desideratur. 
Western Szech'uan: Mao-chou, arid regions of the Min Valley, 
alt. 1300-2000 m., May 25, 1908 (No. 2764). 
Spiraea tortuosa presents a very distinct appearance with its strikingly zigzag 
branches, the small and sparse foliage, and the numerous, small and rather dense 
flower-clusters on very short branchlets. It seems most nearly related to S. hirsuta 
Schneider, but is easily distinguished from that species by its zigzag branchlets, 
the small suborbicular leaves and the small inflorescence. 
