188 SAXIFRAGACE.E. aruncus. 



20 ARUNCUS L. 



Herbaceous perennials with repeatedly ternately divided leaves 

 without stipules and loose panicles of small white flowers termi- 

 nating the branches. Flowers dioecious. Calyx 5-cleft, marces- 

 cent in fruit; disk entire, coherent to the tube. Petals 5. 

 Stamens numerous, hypogynous. Carpels 3-5, distinct, sessile, 

 becoming cartilaginous several-seeded follicles. Seeds with a 

 loose membranaceous testa and no albumen. 



A. vulgaris Eaf. Sylv. Tell. 152. Spiraea Aruncus L. Glabrous: 

 stems stout, 2-6 feet high or more, branching : leaves large, ternately 

 decompound; leaflets thin, sparingly villous beneath, ovate to lanceolate, 

 acuminate, 2-5 inches long isharply and laciniately doubly toothed, the 

 terminal ones broadest : panicles large, compound, pubescent; flowers a 

 line broad, nearly sessile ; petals spatulate ; filaments twice as long as the 

 petals; styles short; carpels 3-5, several seeded, globose, the pedicels 

 reflexed in fruir. Along streams in mountainous districts, Alaska to Cali- 

 fornia and across the Continent. 



Order XXX SAXIFRAGACEiE Dumort. Anal. Fam. 36. 



Herbs with bland watery often astringent juice, alternate or 

 opposite leaves without true stipules and mostly perfect 

 flowers. Sepals 4-5, united or nearly distinct, imbricate in the 

 bud. Petals as many as sepals and alternate with them, rarely 

 wanting. Stamens as many or twice as many as petals, rarely 

 fewer, inserted into the throat of the calyx; anthers introrse. 

 Ovary either free from the calyx or coherent with its tube, 1-3- 

 celled with parietal placentae : ovules mostly numerous : styles 

 distinct or more or less united. Fruit capsular, usually beaked 

 with the distinct summits of the carpels, opening along the inner 

 suture of each, septicidal. Seeds anatropous, usually small and 

 numerous. Embryo straight, in the axis of fleshy albumen : 

 radical cylindrical : cotyledons short. 



*Ovary with 2 or rarely more cells and placentae in the axis, or of as 

 many distinct carpels : fruit capsular or follicular. 



1. Leptarrhena. Petals 5; stamens 5: carpels 2, distinct, free and ex- 

 serted from the small calyx. 



2. Peltiphyllum. Petals deciduous : stamens 10, inserted at the union 

 of the ovary and calyx- tube : carpels distinct, adnate to the tube of 

 the calyx: leaves peltate, radiately veined. 



3. Saxifraga. Petals deciduous: stamens 10, rarely more, inserted 

 under the ovary: carpels 2, rarely 3, more or less united at base, free 

 from or adnate to the base of the calyx. 



4. Saxifragopsis. Petals persistent, soon deflexed : stamens 10, insert- 

 ed at the base of the calyx : carpels united at base, adnate to the lower 

 part of the calyx-tube : leaves palmately veined, the blade obscurely 

 articulated to the petiole. 



5. Sullivantia. Petals persistent : stamens 5. inserted on the throat 

 of the calyx : carpels united at base, adnate to the tube of the calyx. 



6. Boykinia. Petals deciduous, stamens 5 or 10, inserted on the calyx- 

 tube at its union with the ovary : carj>els united at base and adnate 

 to the calyx-tube. 



