88 



THE AMERICAN BOTANIST 



yet they are presented in a way to make the student feel that 

 he is either negHgent or stupid if he fails to work them. 

 These theoretically constructed schemes for elementary teach- 

 ing and these recommendations of untried and impracticable 

 tasks for students sometimes run riot in company with sweep- 

 ing denunciations of our present laboratory courses and sug- 

 gestions for their replacement by hypothetical field courses 

 utterly regardless of the fact that the former, whatever their 

 faults, have been evolved in actual administrative adaptation 

 to the real conditions of elementary work while the proposed 

 substitutes are wholly untried and in the light of existing con- 

 ditions wholly impracticable. — Prof. W. F. Ganong, in 

 Science. 



KEY TO THE POLYPETALOUS DICOTYLEDONES* 



1 Shrubs, trees or woody vines. (2). 



2 Stamens more than twice the number of petals (8). 

 o Leaves opposite (4). 



4 Stamens on the receptacle 

 4 Stamens on the calyx 



Ovaries several, distinct, enclosed 

 Ovaries compound 

 Free from the calyx 

 ,\dherent to the calyx 



^ Leaves alternate. (.5). 



5 Stamens on the calyx tube 

 Fleshy plants 

 Plants not fleshy 



5 Stamens on the receptacle (fi') 

 Petals convolute in bud 

 6 Petals imbricate or valvate in bud (7) 

 T Ovaries compound 



Sepals valvate ; flowers small 

 Sepals imbricate ; flowers large 



7 Ovary or ovaries distinct and simple 

 Petals six, valvate in bud 

 Petals, three to nine, imbricate 

 Climbing vines 

 Trees or shrubs 

 Leaves simple 

 Leaves pinnate 



riypericaceae. (G. Ttl\. B. 024) 



Calycanthaceac. (G. 409. P.. 48.-)) 



Lythraceae. (C. .591. B. f548) 



Saxifragaceae. (G. 444. B. 484) 



Cactaceae. (G. 588. B. 64.'?) 



Rosaceae. (G. 4.54. B. 490) 



Malvaceae. (G. .5W;. B. f!17) 



Tiliaceae. (G. .56.5. B. 616) 



Ternstromiaceae. (G. 570. B. 32.3) 



Anonaceae. (G. 410. B. 410) 



Menispermaceae. (G. 410. B. 434) 



Magnoliaceae. (G. 408. B. 409) 



Mimosaceae. (G. 500. B. .527) 



*'rhe numbers in parenthesis refer to the pages in Gray's and Britton's ALnnnnls re- 

 spectively. For keys to other groups, see earlier issues. 



