2(1). Leaf blades mostly oblong-lanceolate or oblong-ovate, mostly widest at or 

 near the middle, not plicatulate, the teeth antrorsely appressed, 

 extending below the widest part of the leaf 1. P. lanceolata. 



2. Leaf blades mostly ovate or triangular-ovate to rhomboid, often plicatulate, 



widest below the middle, the teeth coarse and divergent, not ex- 

 tending below the widest part of the leaf (3) 



3(2). Mature leaves mostly to 75 mm. long and 20 mm. wide 



2. P. strigulosa. 



3. Mature leaves mostly less than 15 mm. long and 10 mm. wide 



2. P. strigulosa var. sericea. 



4(1). Leaf blades with 1 to 4 pairs of remote salient teeth (5) 



4. Leaf blades with numerous pairs of small mostly antrorse teeth (6) 



5(4). Bractlets 2-3 mm. long, closely imbricate, acute, not conspicuously re- 

 flexed; peduncles 1.5 to 4 times as long as the subtending leaf 

 during anthesis; heads 5-10 mm. thick, becoming elongate-cylindric 

 or oblong in fruit; fruit obovoid 3. P. incisa. 



5. Bractlets 5 mm. long, wide-spreading, the apex long-acuminate and finally 



reflexed; peduncles 0.7 to 1.5 times as long as the subtending leaf 

 during anthesis; heads 7-12 mm. wide, usually not elongating in 

 fruit; fruit oval 4. P. cuneifolia. 



6(4). Leaves uniformly elongate, to 5.5 cm. long, 4-10 mm. wide 



5. P. nodiflora var. longifolia. 



6. Leaves mostly shorter, cuneate-spatulate to rhomboid, 1-3 cm. long (7) 



7(6). Midrib and secondaries usually prominent beneath, often very conspicuous, 

 often impressed above; blades often large and elliptic or rhomboid, 

 coarsely toothed 5. P. nodiflora var. reptans. 



7. Midrib and secondaries usually obscure or indiscernible on both surfaces; 



blades usually small and spatulate or cuneiform (8) 



8(7). Plants usually densely matted, more or less densely strigose-canescent 

 throughout; leaves mostly very small and cuneiform, usually thin- 

 textured and few-toothed, sometimes entire or subentire 



5. P. nodiflora var. rosea. 



8. Plants usually creeping and wide-spreading, open in growth, often with 



ascending branches, usually green and only finely strigillose; leaves 

 mostly larger, cuneate-spatulate or spatulate to obovate, thick- 

 textured, usually more abundantly toothed (9) 



9(8). Teeth on leaf blades mostly rather large, coarse and salient-spreading 



3. P. incisa. 



9. Teeth on leaf blades mostly small and appressed, usually forward-pointing 



5. P. nodiflora. 



1. Phyla lanceolata (Michx.) Greene. Northern frog-fruit. Fig. 655. 



Stems procumbent or ascending, to 6 dm. long, simple or somewhat branched, 

 often rooting at the nodes, glabrous or obscurely white-strigillose with closely 

 appressed hairs; petioles 5-10 mm. long or obsolete, obscurely appressed-strigillose; 

 leaf blades bright-green on both surfaces, oblong to oblong-lanceolate or ovate, 

 18-75 mm. long, 5-30 mm. wide, acute or subacute, sharply serrate to below the 

 middle, widest at or below the middle, narrowed to the cuneate base, rather 

 obscurely appressed-strigillose on both surfaces, venation fiat but conspicuous 

 above, rather prominent and very conspicuous beneath; inflorescence equaling or 

 surpassing the leaves; peduncles 4-9 cm. long, rather sparsely and obscurely white- 

 strigillose; heads at first globose, later cylindric and elongating to 35 mm. and 5-7 

 mm. wide; bractlets obovate, closely imbricate, 3 mm. long, acute, appressed- 

 strigillose; corolla pale-blue, purplish or white. Lippia lanceolata Michx. 



1403 



