414 ROSACEAE 



1. Chamaebatiaria millefolium (Torr.) Maxim. Desert-sweet. Fig. 2374. 



Spiraea millefolium Torr. Pacif. R. Rep. 4: 83. 1857. 

 Chamaebatiaria millefolium Maxim. Act. Hort. Petrop. 6: 225. 1879. 

 Sorbaria millefolium Rocke in Engler & Prantl, Nat. Pflanzenf. 3 3 : 16. 1888. 

 Basilima millefolium Greene, Fl. Fran. 57. 1891. 



Shrub, 1-2 m. high, with the twigs, leaves and inflorescence stellate-pubescent and more 

 or less glandular. Leaves 2-5 cm. long, oblong in outline, primary divisions 15-20 pairs, 4-8 

 mm. long, the secondary division 10—17 pairs, less than 1 mm. long; panicles terminal, leafy, 

 3-10 cm. long; sepals lanceolate, acute, 3-5 mm. long; petals white, broadly obovate, about 

 5 mm. long; follicles 5 mm. long, lanceolate. 



Dry rocky ridges, Arid Transition Zone; southern Idaho to Arizona and the eastern slopes of the southern 

 Sierra Nevada, California. Type locality: low hills and valleys near Williams, Arizona. June-Aug. 



8. HOLODISCUS Maxim. Act. Hort. Petrop. 6:253. 1879. 



Shrubs, with alternate simple leaves and no stipules. Inflorescence racemose or panicu- 

 late. Hypanthium saucer-shaped or hemispheric. Sepals 5, 3-nerved, erect in fruity Petals 

 5, white or pink. Stamens about 20, borne on the disk lining the hypanthium. Pistils 5, 

 alternate with the sepals, pubescent; styles terminal; ovules 2, pendulous. Achenes en- 

 closed in the hypanthium and sepals, hairy, indehiscent, caducous, strongly arched on the 

 lower suture. [Name Greek, meaning entire disk.] 



A genus of 6 or 7 species, native of western North America, Mexico, Central America, and Colombia. Type 

 species, Holodiscus discolor (Pursh) Maxim. 



Leaves 4-10 cm. long, mostly doubly toothed, the blades little or not at all decurrent on the petioles; panicle 

 ample, twice or thrice compound. 1. H. discolor. 



Leaves 0.8-2 cm. long, mostly simple-toothed, distinctly decurrent on the petiole; flowers in a simple raceme or 

 with a few lateral branches below. 



Young twigs and leaves not glandular-atomiferous, more or less silky-villous or tomentose. 



2. H. dumosus saxicola. 



Young twigs and leaves glandular-atomiferous, otherwise glabrous or sparingly short-villous. 



3. H. glabrescens. 



1. Holodiscus discolor (Pursh) Maxim. Ocean Spray. Fig. 2375. 



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

 Spiraea ariaefolia Smith in Rees, Cycl. 33: No. 6. 1816. 

 Schizonotus discolor Raf. New Fl. 3: 75. 1838. 

 Holodiscus discolor Maxim. Act. Hort. Petrop. 6: 254. 1879. 



Shrub 1^ m. high, with brown or purplish exfoliating bark, young twigs more or less 

 villous and tomentose. Leaves broadly ovate or oval, 4-10 cm. long, usually double-toothed, 

 acute at apex, truncate to cuneate at base, but scarcely or not at all decurrent on the petiole, 

 glabrate above, more or less densely villous and tomentose beneath; inflorescence twice or 

 thrice compound, 10-20 cm. long; sepals oblong to oblong-lanceolate, acutish, 1.5 mm. long; 

 petals elliptic, 1.5 mm. long. 



Hillsides and river bottoms, mainly Humid Transition Zone; British Columbia, northern Idaho, and western 

 Montana to northern California. Type locality : banks of the Kooskoosky. June-Aug. 



Holodiscus discolor var. franciscanus (Rydb.) Jepson, Fl. Calif. 2: 166. 1936. Shrub 1.5-7 m. high, 

 closely resembling the typical species but leaves thicker, densely short-pubescent above, rounded or truncate at 

 base; sepals ovate, acute. Coastal region of Oregon and California from Columbia River to Orange County, 

 California. 



2. Holodiscus dumosus subsp. saxicola (Heller) Abrams. Bush Rock-spiraea. 



Fig. 2376. 



Holodiscus saxicola Heller, Muhlenbergia 1: 41. 1904. 

 Sericotheca saxicola Rydb. N. Amer. Fl. 22: 263. 1908. 

 Spiraea discolor var. dumosa S. Wats. Bot. Calif. 1 : 170, in part. 1876. Not 5". dumosa Nutt. 



Low shrub 3-10 dm. high, branched from the base, young twigs villous. Leaves broadly 

 oval to orbicular, 8-15 mm. long, rounded at apex, abruptly narrowed at base into the short 

 winged petiole, simply crenate-serrate, bright green and sparingly pubescent above, tomentose 

 beneath and sparsely villous ; raceme simple or with a few branches below, 3-10 cm. long, 

 villous ; sepals ovate-lanceolate ; petals broadly ovate, 2 mm. long. 



Granitic rock. Boreal Zones; Sierra Nevada, California. Type locality- Donner Pass, Nevada County, 

 California. July-Sept. 



3. Holodiscus glabrescens (Greenm.) Heller. Glandular Rock-spiraea. Fig. 2377. 



Spiraea discolor var. glabrescens Greenm. Erythea 7: 116. 1899. 



Holodiscus glabrescens Heller, Muhlenbergia 1: 40. 1904. 



Sericotheca glabrescens Rydb. N. Amer. Fl. 22: 265. 1908. 



Seriotheca obovata Rydb. N. Amer. Fl. 22: 264. 1908. 



Holodiscus discolor var. glabrescens Jepson, Man. Fl. PI. Calif. 479. 1925. 



Low diffusely branched shrub, 5-15 dm. high, young twigs sparingly villous or glabrous, 



