INTRODUCTORY LESSONS 



IN 



STRUCTURAL BOTAlNY 



SECTION 1.— THE BEGINNINGS OF PLANT LIFE. 



1. If the first rain of the wet season is followed by warm, sunny 

 weather, specks of green will soon appear among the dry stems of last 

 year's weeds; ar.d in fence corners or other eddy nooks where summer 

 winds have drifted seeds and covered them with dust, you ma}^ find i^er- 

 fect mats of baljy j^lants. "With a shovel skim off a few square inches of 

 this plant-bearing soil, and carefully examine it. Except a few green 

 needles, which you recognize as spears of grass, most of these little plants 

 seem to consist of white stems, which split at the top into pairs of green 

 leaves. Looking sharply, you may find between each pair of leaves a 



1 . Seed of Bur-clover just be- 

 fore it appears above groi;ud. 2. 

 Same three days older. 3 . JIus- 

 tard. 4. Bur- clover showing the /r^ 

 first and second plumule leaves; fJ 

 the former simple (apparently), \r^ 

 the 1 itter with three leaflets. 5. ) 

 Mallows (Malvaborealis), show- 

 ing the long-petioled Sf e 1 leaves 

 (Cotyledons , and one plumule 

 leaf unfolded. 6- Filaria (Ero- 

 diiim), -with lobed or sub-com- 

 pound seed leaves. 



tiny bud; or, in the older plants, this may have grown other leaves, which 

 curiously enough are not like the first two. (Figures 1 to G). Searching- 

 through the shovelful of earth you will likely find plants in all stages of 

 growth, from swollen and sprouting seeds to stems, which are just pusli- 

 ing their bowed leaf-heads into the sunlight. Here, then, is material 

 from which you may learn how plants grow; a lesson, remember, which 

 no text-book or schoolmaster can teach you. It will be easier, however, 

 since most of these early wild plants come from very small seeds, to take 



