VOL. II.] 



ROSE FAMILY. 



197 



4. Spiraea Virginiana Britton. Vir- 

 ginia Spiraea. (Fig. 1886.) 



5. Virginiana Britton, Bull. Torr. Club, 17:314. 1890. 



A glabrous much-branched shrub, thebranches 

 forming wands i-4 long. Stipules deciduous 

 or none ; leaves petioled, oblong or oblanceolate, 

 thin, obtuse or acutish at the apex, cuneate or 

 rounded at the base, i^'-^' long, 5 // -8 // wide, 

 green above, pale or slightly glaucous beneath, 

 entire, or with a few low teeth above the middle; 

 flowers white, about 3" wide, in terminal com- 

 pound corymbs; pedicels and calyx glaucous; 

 follicles glabrous. 



On damp rocks, Morgantown, W. Va., to the 

 mountains of North Carolina. June. 



Spiraea sorbifolia, a large shrub with odd-pinnate 

 leaves, lanceolate serrate leaflets, and large panicles 

 of white flowers, much cultivated for ornament, 

 has begun to escape into thickets in the Middle 

 States. It is native of Siberia. 



3. ARUNCUS Adans. Fam. PI. 2: 295. 1763. 



Tall perennial herbs, with large 2-3-pinnate leaves, stipules minute or wanting, and very 

 numerous white dioecious flowers in panicled spikes. Calyx mostly 5-lobed. Petils as 

 many as the calyx-lobes. Stamens numerous, inserted on the calyx fihiments filiform. 

 Pistils usually 3, alternate with the calyx-lobes. Follicles glabrous, at length reflexed, usually 

 2-seeded. Seeds minute, not shining. 



Two known species, the following widely dis- 

 tributed in the north temperate zone, the other 

 Japanese. 



i. Aruncus Aruncus (L,. ) Karst. 

 Goafs-beard. (Fig. 1887.) 



Spiraea Aruncus L. Sp. PI. 490. 1753. 



Aruncus Sylvester Kostel. Ind. Hort. Prag. 15. 



Name only. 1844. 

 Aruncus AruncusKzrst. Deutsch. Fl. 779. 1880-83. 



Glabrous throughout, stem erect, somewhat 

 branched, 3-7 high. Leaves long-petioled, the 

 lower i long or more, pinnate, 3-7-foliolate; 

 leaflets ovate, lanceolate or oval, thin, stalked 

 or sessile, acuminate or acute at the apex, 

 rounded, slightly cordate or sometimes nar- 

 rowjed at the base, sharply doubly serrate or in- 

 cised, 1'-$' long; spikes slender, elongated, 

 erect or spreading; flowers i"-*" wide; follicles 

 short. 



In rich woods, mountains of Pennsylvania to 

 Iowa, south to Georgia and Missouri. Also on the 

 northwest coast from Oregon to Alaska, and in 

 northern Europe and Asia. Ascends to 4200 ft. in 

 North Carolina. May-July. 



4. PORTERANTHUS Britton, Mem. Torr. Club, 4: 115. 1894. 

 [GILLENIA Moench, Meth. Suppl. 286. 1802. Not GIU.ENA Adans. 1763.] 



Erect perennial herbs, with nearly sessile stipulate 3-foliolate or 3-parted leaves, and 

 white or pinkish perfect flowers in loose terminal panicles. Calyx cylindric, persistent, nar- 

 rowed at the throat, ic-nerved, 5-toothed, the teeth imbricated, slightly glandular. Petals 5, 

 linear-lanceolate, spreading, convolute in the bud, somewhat unequal, inserted on the calyx. 

 Stamens 10-20, included; filaments short; anthers large. Carpels 5, villous-pubescent, op- 

 posite the calyx-lobes. Ovules ascending; style filiform. Follicles 5, 2-4-seeded. Seeds with 

 endosperm. [In honor of Thomas Conrad Porter, Professor in Lafayette College.] 



A genus of 2 known species, natives of eastern North America. 



Leaflets serrate ; stipules subulate, mainly entire. i. P. trifoliatus. 



Leaflets incised; stipules .broad, foliaceous, incised. 2. P. stipulatus. 



