1592 



RUSSELIA 



RUSSELIA (Alexander Russell, English physician 

 and author of "Natural History of Aleppo," 1856). 

 ScrophularMcete. About a dozen species of Mexican 

 shrubby plants with angular, usually slender, often 

 pendulous branches: Ivs. usually small becoming scale- 

 like on the branches, opposite or verticillate: fls. bright 

 red in dense or loose corymbs or of a single flower; 

 calvx 5-parted; corolla - tube cylindrical, the lobes 

 spreading and nearly equal; staminodia very short or 

 wanting; stamens 4: capsule subglobose. 2-celled: 

 seeds numerous, very small, winged. A recent synop- 

 sis of Russelia by Dr. B. L. Robinson, with a key to the 

 species, will be found in Proc. Am. Acad. Arts & bci., 

 vol. 35, No. 16, March, 1900. 



Russelias are of easy cultivation. R. juncea and its 

 varieties make excellent basket plants, being almost 

 continuously in bloom. Propagated by cuttings. 

 A. Peduncles 1-3-flowered. 



iuncea, Zucc. (R. scoparia, Hort.). CORAL PLANT. 

 Fig 2220. A tender shrubby plant, with smooth, somewhat 

 rush-like branches, nodding or pendulous at the top: 

 Ivs. linear-lanceolate or ovate, small, becoming minute 

 bracts on the branches: raceme very loose, remotely 

 flowered: peduncles elongated. B.R.21:1773. P.M. 4:79. 

 -Vars. Lem6inei and elegantissima are garden hybrids 

 of B. juncea and R. snrmentosa. They are more florif- 

 erous, especially during the winter, than the type. 

 AA. Peduncles many -flowered. 



sarmentdsa, Jacq. (R. multiflbra, Sims). A tender 

 shrub, becoming 4-6 ft. high: Ivs. opposite, ovate, acu- 

 minate, serrately crenate: fls. verticillate, many in a 

 terminal raceme. B.M. 1528 P.M. 16:163. R.H. 1852:281. 



F. W. BARCLAY. 



KUSSIAN CACTUS. Same as Russian Thistle. 



BUSSIAN FBUITS. See Pomology. B. THISTLE. 

 See Salsola. 



BUST. A name for a class of fungi which produce 

 disease in plants. Rusts are of the class Uredinese. 

 The mycelium branches among the tissues of the host 

 and produces several kinds of spores, either upon 

 the one host ( autcecious ) , or upon different hosts 

 ( hetercecious ) . These spores, as shown typically in the 

 disease of the wheat, are called respectively uredospores, 

 teleutospores, eecidiospores, etc. Recent researches by 

 Eriksson and Henning in Sweden show that the three 

 common rusts which affect the grains, namely: Puccinia 

 graminis (Figs. 2221-2), P. rubigo-vera and P. coronata, 

 can be split up into seven species, characterized by 

 their cultural reactions with a large series of plants, and 

 that Puccinia graminis has besides six specialized 



2221. 



Colonies of Rust ' 

 on the stem of 

 wheat. 



2222. 



The cluster - cup 

 stage of the 

 wheat Rust fun- 

 gus growing on 

 a barberry leaf. 



forms, delimited by differences in the marked capacity 

 of the uredo- or teleutospores to inoculate on different 

 hosts. Several rusts are common on cultivated plants, 

 causing disease; viz., beet rust (LTromyces Betue.), broad 

 bean rust (Uromyces Fabce), white pine rust (Cron- 

 artiumribico lum), asparagus rust (Puccinia Asparagi), 



RYE 



chrysanthemum rust (Puccinia Hieracii), black, or 

 wheat rust (Puccinia graminis), hollyhock rust (Puc- 

 cinia malvacearum) , etc. JOHN W. HARSHBERGER. 



The rusts are fungi constituting a very large and 

 economically important class known as Uredineae. 

 They are all obligatory parasites, attacking a vast num- 

 ber of native and cultivated plants. The mycelium of 



2223. Ruta graveolens. Flowers slightly enlarged. 



the rust fungi exists entirely within the tissues of the 

 host. The spores are formed in masses or sori just be- 

 neath the epidermis. When ripe they break through 

 the epidermis, forming brown patches and spots from 

 which they are scattered. Many of the rusts produce 

 several spore-forms, which often occur in regular succes- 

 sion either on the same host or on different hosts. For 

 example, the wheat rust produces uredospores and teleu- 

 tospores on the wheat and a?cidiospores on the barberry. 



Rusts rarely kill the plants which they affect, and 

 hence in many cases the damage done is not as appar- 

 ent as in many other diseases. In all cases, however, 

 the plants are weakened, and often much disfigured. 

 They are among the most difficult fungous diseases to 

 combat. Spraying has been tried in many instances, 

 but has proved, at most, only partially successful. The 

 most profitable course for overcoming these diseases 

 seems to be the selection of resistant varieties. 



HEINRICH HASSELBRING. 



RUTA (classical name of rue). Rutacece. About 40 

 species from the Mediterranean region of Europe and 

 from Asia. Perennial herbs, often woody at the base, 

 glandular, punctate: Ivs. simple to much pinnate, odor- 

 ous : fls. yellow or greenish, in terminal corymbs or 

 panicles, hermaphrodite, usually 4-merous; petals 4-5, 

 free, often dentate or ciliate; stamens 8-10: ovary ses- 

 sile: capsule 4-5-lobed, indehiscent or dehiscent at apex. 



graveolens, Linn. RUE. HERB OP GRACE. Fig. 2223. 

 A hardy perennial, woody at the base, 1/^-2 ft. high : Ivs. 

 fragrant, much divided; lobes oblong, the terminal ob- 

 ovate: fls. yellow. July. Prop, by division and seeds. 



Fatavina, Linn. (HaplopJiyllum Patavlum, Hort.). 

 A hardy perennial herb 4-6 in. high: Ivs. glabrous, the 

 lower oblong- spatulate, narrowed at the base, the others 

 trisected and laciniate: corymb dense; pedicels some- 

 what longer than the fls. : fls. golden yellow. June, July. 



F. W. BARCLAY. 



RUTABAGA, or SWEDISH TURNIP. Consult Bras- 

 sica campestris, page 177; also Turnip. 



RUTLAND BEAUTY is Convolvulus Sepium. 

 RYE, See Secale. RYE. Wild. See Elymus. 



