ROSE FAMILY 409 



1. LYONOTHAMNUS A. Gray, Proc. Amer. Acad. 20:291. 1885. 



Trees with reddish brown shreddy bark. Leaves opposite, persistent, simple and entire, 

 pinnatifid or pinnately compound. Flowers in terminal compound cymes, perfect. Hypan- 

 thium hemispheric, free from the ovary. Sepals 5, persistent. Petals 5, clawless. Stamens 

 15, borne on the disk lining- the hypanthium. Pistils 2, 1-celled. Style stout, stigma small. 

 Ovules 4 in each ovary, pendulous. Fruit a pair of follicles; seeds 4, oblong. [Name for 

 the discoverer, W. S. Lyon, and Greek for shrub.] 



A monotypic genus restricted to the islands of southern California. 



1. Lyonothamnus floribundus A. Gray. Catalina Ironwood. Lyonothamnus. 



Fig. 2361. 



Lyonothamnus floribundus A. Gray, Proc. Amer. Acad. 20: 292. 1885. 



Evergreen tree, 5-15 m. high, with a rather narrow crown and reddish brown shreddy 

 bark; young twigs pubescent. Leaves evergreen, firm, oblong-lanceolate, 10-15 cm. long, 

 entire, crenate-serrate, or occasionally lobed below, short-petioled, tomentose or glabrate 

 beneath, dark glossy green above; cyme 1-2 dm. broad, densely many- flowered; hypanthium 

 densely tomentose ; petals white, suborbicular, 4-5 mm. long ; follicles glandular-pubescent. 



Canyon slopes, Upper Sonoran Zone; restricted to Santa Catalina Island, southern California. May-July. 



Lyonothamnus floribundus var. asplenifolius (Greene) Brandg. Zoe 1: 136. 1890. {Lyonothamnus 

 asplenifolius Greene, Bull. Calif. Acad. 1: 187. 1885.) Leaves pinnately divided into 3-7 leaflets, these oblong- 

 lanceolate, pinnatifid into broad oblique lobes with narrow sinuses. Santa Rosa, Santa Cruz, and San Clemente 

 Islands, intergrades with the typical form on Santa Catalina. The variety is a unique and attractive orna- 

 mental tree. 



2. PHYSOCARPUS Maxim. Act. Hort. Petrop. 6:219. 1879. 



Shrubs with exfoliating bark and petioled palmately lobed leaves. Flowers in terminal 

 corymbs. Hypanthium campanulate, 5-lobed, stellate-pubescent. Petals 5, white, spread- 

 ing. Stamens 20-40, inserted on a disk, in the throat of the hypanthium. Pistils 1-5, more 

 or less united at the base ; styles elongated ; stigmas capitate. Follicles inflated, at length 

 deciduous along both sutures. Seeds 2-4, ovoid, with a bony shining coat; endosperm 

 copious. [Greek, meaning bellows or bladder, and fruit.] 



Species about 10, one in Manchuria, the others in North America. Type species, Physocarpus amurensis 

 Maxim. 



Pistils 2—5 ; stamens similar. 



Follicles 3-5, united at the base, glabrous. 1. P. capitatus. 



Follicles 2, united half their length, or only 1, stellate. 2. P. malvacetcs. 



Pistil 1 ; alternating stamens long and their filaments more dilated. 3. P. alternans. 



1. Physocarpus capitatus (Pursh) Kuntze. Pacific Ninebark. Fig. 2362. 



Spiraea capitata Pursh, Fl. Amer. Sept. 342. 1814. 



Physocarpa tomentosa Raf. New Fl. 3: 74. 1838. 



Neillia opulifolia var. mollis Brewer & Wats. Bot. Calif. 1: 171. 1876. 



Neillia capitata Greene, Pittonia 2: 28. 1889. 



Physocarpus capitatus Kuntze, Rev. Gen. PI. 2: 219. 1891. 



Opulaster opulifolius var. capitatus Jepson, Fl. W. Mid. Calif. 276. 1901. 



Opulaster cordatus Rydb. N. Amer. Fl. 22: 242. 1908. 



Shrub with erect or surculose branches, 1-5 m. high. Leaves broadly round-ovate,_ 3-5- 

 lobed, the lobes incised or doubly serrate, truncate to cordate at base, glabrous or slightly 

 pubescent above, stellate-pubescent or glabrous beneath, 3-6 cm. long, on petioles 1-2 cm. 

 long; corymbs hemispherical, densely flowered; pedicels and hypanthium densely stellate; 

 petals 3 mm. long; follicles 3-5, glabrous or more or less stellate. 



Stream banks and rocky slopes, Transition and Canadian Zones; southern British Columbia and Idaho, south 

 to the Sierra Nevada and California Coast Ranges as far as Santa Barbara County. Type locality: northwest 

 coast of America. May-Sept. 



2. Physocarpus malvaceus (Greene) Kuntze. Mallow-leaved Ninebark. 



Fig. 2363. 



Spiraea opulifolia var. pauciflora Torr. & Gray, Fl. N. Amer. 1: 414. 1840. 

 Neillia malvacea Greene, Pittonia 2: 30. 1889. 

 Physocarpus malvaceus Kuntze, Rev. Gen. PI. 219. 1891. 

 Opulaster malvaceus Kuntze, Rev. Gen. PI. 949. 1891. 

 Physocarpus pauciflorus Piper, Fl. Palouse Reg. 94. 1901. 



Shrub, 1-2 m. high, with stellate or glabrous, brown branches. Leaves round-ovate 3-5- 

 lobed and more or less doubly crenate-serrate, 2-6 cm. long, usually cordate at base, stellate- 

 pubescent on both surfaces or sometimes glabrous; petioles 1-2 cm. long; pedicels and hypan- 

 thium densely stellate; corymbs hemispherical, 3-5 cm. broad; petals rounded, 4-5 mm. long; 

 follicles 2, united nearly two-thirds their length. 



Stream banks and moist hillsides, Transition and Canadian Zones; British Columbia to Oregon, Montana, 

 and Utah. Type locality: shores of Lake Pend Oreille, northern Idaho. June-Sept. 



