EOSACEAE. — 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. rolundifolia Hemsley in Joiir. Linn. Soc. XXIII. 224 



(1887). 

 Spiraea Maximowicziana Schneider, III. Handb. Lauhholzk. I. 461 (1905). 



Western Hupeh: Changlo Hsien, thickets, side of streams, alt. 

 600-1000 m., May 1907 (No. 2770) ; without precise locaUty, 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 ramuhs 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 

 paucifohatorum, 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, petaHs triente breviora; discus conspicuus, lobatus, 

 purpureo-brunneus, lobi distincti cum staminibus interioribus alter- 

 nantia, dorso canaliculati 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 branchlcts. 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. 



