122 CISTACEAE 



bushy or often conical crown, the branchlets numerous, very slender, divided into short articulate joints, pale 

 glaucous-green. Leaves minute and cusp-like; flowers in slender racemes forming panicles, 5-raerous. A native 

 of western Asia frequently planted as a windbreak in the Sacramento and San Joaquin Valleys and in southern 

 California, especially in the desert regions, but seldom growing spontaneously. The branchlets exude a salt that 

 forms encrustations, hence the name. 



Family 98. CISTACEAE. 



RocKROSE Family. 



Shrubs or low woody plants, with alternate or opposite simple leaves. Flowers 

 regular, generally perfect, solitary, clustered, racemose, or paniculate. Sepals 3 or 

 5, persistent ; when 5 the outer ones smaller and bract-like, the inner 3 convolute. 

 Petals 3 or 5 or sometimes none, fugacious. Stamens many, hypogynous. Pistil 1 ; 

 ovary sessile, 1- to several-celled; style 1; stigma entire or 3-lobed; ovules ortho- 

 tropous, attached by a slender funiculus. Fruit a capsule, dehiscent by valves. Seeds 

 several to many ; embryo slender ; endosperm present, farinose. 



A family of 8 genera and about 150 species of wide geographical distribution. 



1. HELIANTHEMUM [Tourn.] Mill. Card. Diet. abr. ed. 4. 1754. 



Low shrubs or perennial herbs with woody bases. Leaves alternate, simple, and 

 entire. Flowers all alike, with rather showy yellow petals, or of two sorts, showy petal- 

 bearing ones, and small apetalous cleistog-amous ones. Sepals 5, the 2 outer_ smaller. 

 Petals 5, yellow, fugacious. Stamens numerous. Carpels 3; ovary with 3 parietal pla- 

 centae or false partitions. [Name Greek, from two words meaning sun and flower.] 



A genus of about 70 species of wide geographical distribution. The Pacific States species belong to the 

 section Spartioides, characterized by the broom-like habit, and the absence of cleistogamous flowers. Type species, 

 Helianthemum Chamaecistus Mill. 



Inflorescence puberulent, not glandular. 



Petals 4-6 mm. long; plants 2-3 dm. high. 1. H. scoparium. 



Petals 8-12 mm. long; plants 3-8 dm. high. 2. H. Aldersonii. 



Inflorescence glandular-pubescent. 3. H. Greenei. 



1. Helianthemum scoparium Nutt. Common Rush-rose. Fig. 3248, 



Helianthemum scoparium Nutt. in Terr. & Gray, Fl. N. Amer. 1: 152. 1838. 

 Halimium scoparium Gross. Pflanzcnreich 4''*3: 35. 1903. 

 Crocanthemiim scoparium Millsp. Field Mus. Bot. Ser. 5: 175. 1923. 



Low tufted plant with many spreading branches from a woody crown, 2-3 dm. high, 

 minutely stellate-pubescent. Leaves narrowly linear, 1-3 cm. long, canescent with a close stellate 

 pubescence or glabrate ; flowers solitary in the axils of the upper leaves, pedicelled, formmg a 

 leafy-bracted, few-flowered terminal raceme ; pedicels 3-6 mm. long ; inner sepals ovate-lanceo- 

 late, 4-5 mm long, stellate-pubescent or glabrate, the outer shorter and narrowly linear ; petals 

 broadly obovate, &-10 mm. long. 



Dry usually sandy rocky soils, along the coast. Humid Transition Zone; Mendocino County to Monterey 

 County. California, and also on Santa Cruz Island. Type locality: "Dry hills around Monterey. Dec-Sept. 



Helianthemum scoparium var. vulgare Jepson, Man. Fl. PI. Calif 641. 1925. Branches strictly erect 

 and broom-like. Leaves narrowly linear, early deciduous, those of the paniculate inflorescence reduced to small 

 bracts- outer sepals 3-4 mm. long. Dry hillsides, mainly in chaparral. Upper Sonoran Zone; Coast Kanges 

 from Lake County to San Diego County; also in the foothills of the Sierra Nevada, California. Type locality: 

 Coulterville, Mariposa County, California. 



Helianthemum suffrutescens Schreiber, Madrono 5:81. fig. 1. 1939. Suffrutescent, 4-8 dm. high, vir- 

 gately branched at base, rather densely leafy, canescent throughout with a short stellate-pubescence. Leaves 

 linear-lanceolate to ohlanceolate, densely stellate-pubescent, persistent; flowers panicu ate, leafy-bracted; petals 

 about 6 mm. long. Dry slopes. Upper Sonoran Zone; vicinity of Bisbee Peak and Michigan Bar, Amador 

 County California. This recently discovered, apparently local, species would seem to be quite distinct, espe- 

 cially from Helianthemum scoparium var. vulgare Jepson, which is the other representative of the genus in the 

 Sierra Nevada foothills. Type locality: Bisbee Peak. 



2. Helianthemum Aldersonii Greene. Alderson's Rush-rose. Fig. 3249. 



Helianthemum Aldersonii Greene, Erythea 1: 259. 1893. 



Halimium Aldersonii Standley, Contr. U.S. Nat. Herb. 23:832. 1923. 



Crocanthemum Aldersonii Janchen in Engler & Prantl, Nat. Pflanzenf. ed. 2. 21 : 305. 1925. 



Helianthemum scoparium var. Aldersonii Munz, Man. S. Calif. Bot. 316. 1935. 



Low plant with a woody base and erect broom-like branches 5-8 dm. high. Leaves linear, 

 or the lower sometimes narrowly ohlanceolate, 2-6 cm. long, pale green and glabrate or some- 

 what stellate-pubescent; inflorescence paniculate or somewhat corymbose-paniculate; peduncles 

 in the axils of small bracts; inner sepals 5-6 mm. long; petals 8-12 mm. long. 



Dry rocky or sandy soils. Upper Sonoran Zone; interior valleys and foothills of cismontane southern Cali- 

 fornia Caion Pass to San Diego County, Californria, and adjacent Lower California Type locality: mountains 

 of the southern borders of San Diego County, California, among rocks in hard, sterile granitic soil. heb.-July. 



