EXERCISE XII.' 

 THE PROPAGATION OF HIGHER PLANTS. 



Supplies for a Laboratory Section of Twelve. Eighteen six-inch flower pots, a sufficient quantity of rich, 

 black soil to till the flower pots; two or three sweet potatoes or horseradish roots; geranium; grape, willow, or 

 Cottonwood cuttings; leaf cutting from begonia plant; petri dish; tooth picks; Bermuda grass underground stems; 

 two or three common potatoes; a glass; pieces of willow and apple branches one inch in diameter; one dozen 

 apple seedlings one year old (these may be secured from some local r nursery) : one dozen scions cut from last 

 summer's growth of a good apple tree; grafting wax (See Exercise XXXVI, Part C) ; cloth for bandage; oat, 

 corn, bean, alfalfa, radish, and beet seed. 



Part A. Propagation by Roots. 



1. The sweet potato is an enlarged root. Gardeners obtain the best results by multiply- 

 ing or propagating the plant from the root.* Cuttings from the plant are, however, some- 

 times used. 



Plant a sweet potato root about two inches deep in a six inch flower pot. Record results 

 in the following order: (a) Date of planting, (b) Date of first appearance above surface, 

 (c) Time required to reach a height of three inches. 



2. After the plants thus grown have reached a height of three inches pull them and 

 transplant one of the plants to another pot. (a) Record the date of pulling and transplant- 

 ing, (b) Time required for the original sweet potato to produce a new set of plants, (c) 

 Did the plant which you transplanted grow? 



Part B. Propagation by Cuttings from Stems or Leaves. 



3. Many herbaceous and woody plants can be propagated by cuttings taken from their 

 stems or leaves. Most house plants may be propagated in this way, also such plants as cur- 

 rants, grapes, cottonwoods and willows. 



A geranium may be used to illustrate the propagation of a herbaceous plant by means of 

 a cutting taken from the stem. For this experiment select a sound geranium cutting about 

 four inches in length. Make a hole in the soil about two inches deep. Insert the cutting in the 

 hole and press the soil firmly about it. If the cutting is leafy some of the leaves should be 

 removed. The leaf area, thus reduced, transpires less moisture and gives the roots a chance 

 to establish themselves before the stem becomes too dry. (a) About how many days were 

 required for the geranium cutting to show marked signs of growth? (b) Soon after the cut- 

 ting starts growing, pull it up and examine its root system. From what place on the cutting 

 do most of the roots arise? 



4. To illustrate the propagation of a woody plant by means of a cutting taken from the 

 stem, cut from a last year's growth of grape vine** a section having three buds. Set the cut- 

 ting in a flower pot so that two of the buds will be below the surface of the soil, (a) About 

 how many days are required for the cutting to show marked signs of growth? (b) Soon 

 after the cutting starts growing, pull it up and examine its root system. From what place on 

 the cutting do most of the roots arise? (c) From what place do leaves arise? 



5. The begonia plant is one which may be propagated from leaf cuttings. Cut a sound 

 leaf from a begonia plant. Lay the leaf on moist soil right side up. Fasten it down by run- 

 ning toothpicks through it at several places. Cover the leaf over with a petri dish, (a) After 

 a time observe from what point roots grow most readily, (b) May more than one plant be 

 started from a single leaf? 



•Note: The horseradish or dandelion may also be used to illustrate the propagation of plants from the root 

 "Note: For this purpose, currant, cottonwood, and willow cuttings are at least as good as grape. 



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