PHYLLOTAXY, OR LEAF ARRANGEMENT 41 



nition, the single leaf of the orange and lemon is compound, 

 for it is jointed to the petiole like those of the ash and 

 hickory. This view is supported by the fact that some 

 species- of orange have trif oliolate leaves. 



PRACTICAL QUESTIONS 



1. State whether such of the following leaves as you can find are 

 lobed or compound : cinquefoil, wood anemone, tree fern (^Polypodium 

 incanuni), buttercups, Dutchman's breeches {Diceiitra), mayweed, 

 chamomile, yarrow, tickseed (coreopsis), shield fern, agrimony, tomato, 

 tansy, cosmos, cypress vine, wild carrot, larkspur, strawberry, monks- 

 hood, celandine. 



2. Which of the following are pinnately and which palmately 

 trifoliolate ? Lucerne, red clover, Japan clover {Lespedeza striata), 

 beggar's ticks {Desmodiimi), sweet clover {Melilotiis), kidney bean, 

 strawberry. 



3. Name some of the favorite shade trees of your neighborhood; 

 do they, as a general thing, have their leaves entire, or branched and 

 compound ? 



4. Which of the following are the better shade trees, and why : pine, 

 white oak, mimosa {Albiszia), sycamore, locust, horse-chestnut, fir, 

 maple, linden, China tree, cedar, ash? 



5. Which would shade your porch better, and why: cypress vine, 

 grape, gourd, morning-glory, wistaria, clematis, smilax, kidney bean, 

 Madeira vine, rose, yellow jasmine, passion flower? 



PHYLLOTAXY, OR LEAF ARRANGEMENT 



Material. — Twigs of any kinds of plants with opposite and alter- 

 nate leaves. For the different orders of alternate arrangement, elm, 

 ivy, basswood, wandering Jew, or any kind of grass will show the first ; 

 alder, birch, or any kind of sedge, the second ; peach, oak' cherry, or 

 almost any of our common trees and shrubs, the third (in cities, a 

 potato plant grown in a pot may be used). In selecting specimens, 

 choose straight, young twigs in order to avoid confusion from twisting 

 of the stem that often occurs in older specimens on account of light 

 exposure, or from other causes. 



50. Alternate and Opposite Leaves. — Compare the ar- 

 rangement of leaves on a twig of elm or basswood, or on 

 a culm of grass, etc., with that of the foliage of the maple, 

 lilac, or honeysuckle. Make a vertical diagram of each, as 



