Parr 3, 1908] ROSACEAE 255 
1. Luetkea pectinata (Pursh) Kuntze, Rev. Gen. 217. 1891. 
Saxtfraga pectinaia Pursh, Fl. Am. Sept. 312. 1814. 
Luetkea sibbaldioides Bong. Mém. Acad, St. Petersb, VI. 2: 130. 1832. 
Eriogynia pectinata Hook. Fl. Bor. Am. 1: 255, 1832. 
Spiraea pectinata T. & G. Fl. N. Am. 1: 417. 1840. 
Saxifraga caespitosa A, Gray, Proc. Am. Acad. 8: 383. 1870. 
Flowering shoots 5-15 cm. high, leafy, glabrous; leaves 1-1.5 cm. long, dissected into 
linear acute divisions, grooved above, glabrate; raceme short, 1-5 cm. long; bracts ternate, 
or the upper ones entire ; hypanthium hemispheric, about 2mm. wide; sepals ovate, acute, 2 
mm. long, glabrous; petals white, orbicular or rounded-obovate, 3-3.5 mm. long; stamens 
and styles included ; follicles about 4 mm. long, in age nearly glabrous and shining. 
TYPE LOCALITY : On the northwest coast [of America]. 
DISTRIBUTION : Mountains from Bering’s Strait to Oregon and the Canadian Rockies. 
ILLUSTRATIONS: Bong. /oc. cit. pl. 2; Hook, Fl. Bor. Am. ~/. 88; Bot. Gaz. 15: pl, 14. 
6. ARUNCUS (L.) Adans. Fam. Pl. 2: 295. 1763. 
Perennial herbs with thick rhizomes, twice or thrice ternate-pinnatisect leaves, and no 
stipules. Inflorescence a large panicle with spike-like branches. Flowers dioecious. 
Hypanthium of the staminate flowers flat or saucer-shaped, pentagonal. Sepals triangular, 
valvate. Petals 5, orbicular to spatulate, white. Stamens 15-30; filaments subulate, dis- 
tinct, long-exserted ; anthers didymous. Disk 5-lobed. Pistils 3-5, rndimentary, style-less. 
Pistillate flowers much smaller. Petals elliptic to oblanceolate. Stamens rudimentary ; 
filaments short; anthers minute, empty. Pistils 3-5, distinct; styles short, obliquely ter- 
minal; stigmas capitate; ovules 8-12, pendulous. Follicles oblong, cartilaginous, dehiscent 
along the ventral suture and then splitting dorsally at the apex, in our species reflexed ; 
Seeds few, attenuate at each end, with loose membranous coat ; endosperm present. 
Type species, Spiraea Aruncus L. 
. Follicles about 3 mm. long. 
Petals of the staminate flowers broadly rounded-obovate, about # as broad 
as long; leaflets lanceolate with long acumination. 1. A. acuminatus. 
Petals of the staminate flowers spatulate, #-$ as broad as long; leaflets 
ovate, with shorter acumination. 2. A. Aruncus. 
Follicles about 2 mm. long. 
Leaves decidedly hairy, rather firm and dull; follicles about 3 mm. thick. 3. 4. pubescens, 
Leaves glabrous or nearly so, shining, thin ; follicles about 1 mm. thick. 
Inflorescence open, with long branches; leaflets doubly serrate. 4. A. allegheniensis. 
Inflorescence dense, with short branches; leaflets laciniate. 5. A, kamchaticus. 
1. Aruncus acuminatus (Dougl.) Rydberg, sp. nov. 
Spiraea Aruncus Hook. Fl. Bor. Am.1: 173. 1832. Not S. Aruncus \. 1753. 
Spiraea acuminata Dougl.; Hook. Joc. cit. as a synonym. 
Stem 1-2 m. high, glabrous; lower leaves thrice compound, first ternate; the lower 
divisions usually pinnate with 5 leaflets, and the terminal again ternate; the lower divi- 
sions of this with 3 and the terminal one pinnate with 5 leaflets; leaflets 3-12 cm. long, 
lanceolate, long-acuminate at the apex, acute, truncate or subcordate at the base, sharply 
and doubly serrate, thin, more or less hairy on both sides, especially along the veins, or 
sometimes glabrous; the upper leaves less compound and sometimes pinnately 5-foliolate ; 
panicles terminal and axillary, 14 dm. long, that of the staminate plant often more leafy 
and with shorter branches; branches 3-15 cm. long, in fruit very lax; petals of the stami- 
nate flowers broadly rounded-obovate, about 1 mm. long and ¢ as broad; those of: the pis- 
tillate flowers slightly smaller, elliptic; follicles about 3 mm. long and 1 mm. thick, 
shining. 
TYPE LOCALITY: Mouth of the Columbia. 
DISTRIBUTION: Moist woods and along streams, from northern Oregon to Alaska, and inland 
to the Selkirk Mountains of British Columbia. 
2. Aruncus Aruncus (L,.) Karst. Deuts. Fl. 779. 1882. 
Spiraea Aruncus I. Sp. Pl. 490. 1753. 
Ulmaria Aruncus Hill, Hort. Kew. 214. 1769. 
Aruncus vulgaris Raf. Sylva Tell. 152. 1838. 
Aruncus sylvester Kostel. Ind. Hort. Prag. 15. 1844. 
Astilbe Aruncus Trev. Bot. Zeit. 13: 819. 1855. 
Spiraea paniculata St.-Lag. Ann. Soc. Bot. Lyon 7: 135. 1880. 
