386 



HENDERSON'S HANDBOOK OF PLANTS 



KUM 



vation, and are worthy of a place in every 

 good collection. Propagated by cuttings in 

 heat. 



Ru'mex. Dock, Sorrel. From rumo, to suck ; 

 in allusion to tin; practice among the Romans 

 of sucking the leaves to allay thirst, Nat. Ord. 

 PolijgonaceoR. 



Most of the species are common weeds. 

 The leaves of R. acetosa are sometimes used 

 as a pot-herb, or "greens." R. acetosella is a 

 small-growing species, well known for its 

 acidity, and popularly called Sorrel. It is 

 justly regarded as a nuisance. R. scutatiiH. 

 the Buckler-shaped or Fren(;h Sorrel, is a 

 hardy perennial, a native of France and Italy. 

 It is considered of great importance in French 

 cookery, and is botii agreeable to eat and 

 very wholesome, although but little valued in 

 this country, except at some of the most 

 fashionable tables. It is extensively culti- 

 vated on the continent, and in the markets of 

 Paris is nearly as atjundant as Peas are in 

 ours. It abounds in oxalic acid, and is re- 

 garded as a powerful anti-scorbutic. 



Rumfo'rdia. The only species of this genus, 

 R.floribunda, is a handsome, opposite-leaved 

 Mexican bush of the ComposUfB family, differ- 

 ing from Heliopsis chielly in habit. The whole 

 plant is smooth, and the erect stems, furnished 

 with ample, glossy leaves, terminate in a pan- 

 icle of very numerous bright-j'ellow flower- 

 heads, each about an inch across, and inter- 

 spersed with oblong bracts. Propagated by 

 division or by seeds. 



Runcinate. Curved in a direction from the 

 apex to the base, as the leaf of the Dandelion. 



Runner. A prostrate, slender stem, rooting at 

 its extremity or elsewhere, as in the Straw- 

 berry. 



Running Blackberry. See Rubu». 



Running Cedar. Lycopodium dendroideum. 



Rupestris. Rupicola. Growing on rocks or 

 in rocky places. 



Ru'scus. Formerly Bnisais. Butcher's Broom. 

 From hrxiscus, derived from the Celtic beu.s, 

 box, and keUn, holly ; Box Holly or Butcher's 

 Broom. Nat. Ord. Liliacece. 



Very curious evergreen shrubs, most of 

 which bear their flowers and fruit on their 

 leaf-like branches. All the species prefer 

 shady situations under the drip of trees, 

 where but few other plants will grow ; and 

 they are all readily increased by suckers from 

 their roots, which they throw up in abun- 

 dance. They are natives of Europe and the 

 whole Mediterranean region from Madeira to 

 the Caucasus. R. racemosvs is sometimes 

 called the Alexandrian Laurel. 



Rush. See Juncus. 



Rush. Flowering. See Biitomus. 



Rush-Lily. The genus Sisyrinchium. 



Russe'lia. Named in honor of Dr. Alexander 

 Russel, author of a Natural History of Aleppo. 

 Nat. Ord. ScrophulariacecE. 



A genus of small shrubs and herbaceous 

 plants from Mexico and the Antilles. R. 

 juncea, a very pretty species, with bright 

 scarlet flowers, produced in axillary corymbs, 

 is a plant of slender habit, and well adapted 

 for basket work. It was introduced from 

 Mexico in 1833, and is propagated by cuttings. 



RUS 



Russian Mats. An article of commerce manu- 

 factured from the inner bark of the Lime 

 tree ( Tilia), formerly much used for protect- 

 ing frames, tying purposes, etc. 



Rust. This term is used for a destructive form 

 of disease affecting many widely different 

 kinds of plants. It is known by the dry, 

 shriveled, or curly appearance of the foliage, 

 the leaves being less or more discolored with 

 blackish blotches or spots. It is not always 

 easy to determine the cause, but we think it 

 is safe to say that in many plants it is owing 

 to a weakened condition of the plant that in- 

 vites the attacks of parasites, causing the 

 "rust." This we have proved to be the case 

 so often in our practice that we now no longer 

 doubt on the subject. 



We find, lor example, if we leave such plants 

 as Heliotropes, Verbeiuis, Lantanas, Pelar- 

 goniums, or other plants subject to the dis- 

 ease known as " black rust," so that they be- 

 come enfeebled for want of pot room, they 

 are almost certain to be affected. A few 

 years ago we tried an expc^riment on one hun- 

 dred each of Heliotrope and Verbena plants 

 (that were in fine, healthy condition, growing 

 in two-inch pots), of shifting one-half of each 

 lot into three-inch pots, the other half being 

 allowed to remain unshifted. The shifted 

 plants grew vigorously, and in six weeks were 

 twice the size of tiie others, and in tine, vigo- 

 rous health ; while those unshifted, becoming 

 impoverished for want of new soil, were 

 stunted, and nearly all became affected by 

 " black rust." 



The examination of the diseased leaves by 

 a powerful microscope revealed numbers of 

 crab-like mites feeding on the leaves, while 

 on health}^ leaves of the same plant not a par- 

 asite could be found. The inference then is, 

 that the weakened condition of the plant 

 made it a congenial soil for the deposit of the 

 germ of this parasitical insect. Another kind 

 of " rust," evidently distinct from the preced- 

 ing, is now one of the most serious obstacles 

 in the forcing of Lettuce under glass, whole 

 crops being utterly destroyed by it. We are 

 inclined to believe that the Lettuce rust is 

 the Avork of a vegetable parasite, as a micro- 

 scopic examination of the diseased leaves 

 shows a fungoid structure very similar to 

 Rose mildew. The only remedy we can ad- 

 vise in this case is to work with young plants 

 on fresh soil as far as practicable. The usual 

 method of obtaining Lettuce plants for forc- 

 ing is to use plants sown or planted in cold 

 frames in fall for all the plantings during the 

 entire winter ; but we have found that such 

 plants are "more liable to the disease than 

 those sown later ; and now the most success- 

 ful growers of Lettuce for winter use only the 

 cold-frame (fall-sown plants) for their first 

 crop, which is usually ready at Christmas, 

 while for the succession crops, new sowings 

 are made about six weeks before the plants are 

 needed, it being found that these fresh young 

 plants ai-e less liable to the rust than the 

 others. 



Rustic "Work. This term is applied to all or- 

 naments or erections made of gnarled and 

 twisted branches or roots, undressed timber, 

 or other similar materials, as nearly as possi- 

 ble in their natural state. Its construction 

 requires natural aptitude and good taste, and 



