HENDERSON'S HANDBOOK OF PLANTS. 



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bright colors should be used to contrast 

 with the ground- work of white. A simple 

 yet elegant effect is produced by plant- 

 ing with Scarlet Geraniums, and nothing 

 else. But if desired to be varied, bright 

 colored Verbenas, Coleus, Lobelias, Rose- 

 colored Geraniums, Golden Moneywort, 

 and many other similar plants can be 

 used with effect. A rockery so formed 

 and planted, without having any preten- 

 sions to being natural, is always an at- 

 tractive and interesting object on a well- 

 kept lawn. If cement or " water-lime " 

 is used instead of lime, the rock-work 

 can be made of a pleasing drab color. 

 Boot. The descending axis. See Radix. 

 Rotate, Rotceform. Resembling a wheel. 

 Rotation of Crops. All observing cultivators 

 soon discover that, no matter how fertile 

 a soil may be, the same kind of crop can- 

 not be grown so well on it successively, 

 as if it were alternated with a crop of an 

 entirely different character. No satisfac- 

 tory reason can be assigned for this that 

 we know off, unless in the familiar case 

 of the Cabbage crop. We find that if 

 Cabbages on most soils are grown two 

 years in succession, the crop will be af- 

 fected by the disease known as "Club 

 Root," (which see;) but in this particular 

 instance we get at a tangible cause. A 

 great many theories have been assigned 

 why the same crops deteriorate by being 

 grown successively on the same soil, but 

 they have been far from satisfactory, and 

 in no case that we know of, unless in the 

 case of the Cabbage, or Brassica tribe, have 

 they led to any beneficial practical re- 

 sults. The following general rules have 

 been laid down as a guide : 



First. Plants of the same natural order 

 should not be planted to succeed each 

 other. Second. Crops which for a num- 



KUS 



ber of years occupy the ground, such as 

 Strawberries, Rhubarb, or Asparagus, 

 should be succeeded by annual crops, 

 such as Cabbages, Lettuce, or Radishes. 

 Third. Crops grown for their heads, such 

 as Cabbage, Cauliflower, or Lettuce, 

 should be succeeded by plants grown for 

 their roots, such as Parsnips, Carrots, or 

 Beets. It is not always practicable to 

 vary crops according to rules, nor should 

 such rules be taken as arbitrary, but only 

 as a guide. When vegetables or fruits 

 are grown for market, the necessities of 

 the cultivator compel usually double 

 crops of the land each season, and that, 

 with heavy manuring and deep cultiva- 

 tion, seems to do away, to a considerable 

 extent, with any need for systematic ro- 

 tation, which would often be found to be 

 impracticable. As has been previously 

 said, the crops of afl others that we find 

 most benefited by change are the Cab- 

 bage tribe, together with the allied fam- 

 ilies of Turnip, Radish, etc. While, on 

 the other hand, Onions never seem to be 

 injured by successive plantings on the 

 same soil When space is limited, or 

 when it is not convenient to rotate crops, 

 the next best thing is deep culture, by 

 trenching or subsoiling, which see. 



Rudimentary. In an incomplete condition. 



Ruga. A wrinkle; hence rugose, covered 

 with wrinkles. 



Rupestris. Growing on or near rocks. 



. 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 deter- 

 mine the cause, but we think it safe to say 

 that in many plants it is owing to a weak- 



