103 



16a. Leaves all basal; flowers on leafless stalks (1 dm. high or 

 less; flowers pink or white, summer) 



Mudwort, Limosella aquatica var. tenuifolia. 



16b. Leaves opposite (those subtending the flowers may be al- 

 ternate) 20. 

 16c. Leaves alternate or irregularly scattered 17. 



17a. Leaves entire 18. 



17b. Leaves pinnately lobed or incised 8a. 



17c. Leaves palmately veined and lobed; stem trailing (flowers blue, 

 summer) Kenil worth Ivy, Linaria cymbalaria. 



18a. Corolla-tube less than 1 cm. long, spurred 19. 

 18b. Corolla more than 2 cm. long, not spurred (3 8 dm. high; 

 flowers red-purple, summer) Snapdragon, Antirrhinum majns. 



19a. Stem and foliage pubescent (1 3 dm. high; flowers blue, sum- 

 mer) Small Snapdragon^ Linaria minor. 



19b. Stem and foliage glabrous (2 6 dm. high; flowers blue, sum- 

 mer) Toad-flax, Linaria canadensis. 



20a. Leaves with 1 or 2 lobes near the base (3 5 dm. high; 

 flowers purple, summer) Gerardia, Gerardia auriculata. 



20b. Leaves linear (2 6 dm. high; flowers rose-purple, summer 



and autumn) (Gerardia) 21. 

 20c. Leaves lanceolate or broader, not lobed 26. 



21a. Pedicels equaling or but little longer than the calyx, and con- 

 spicuously shorter than the subtending leaf 22. 



21b. Pedicels much longer than the calyx, and generally equaling or 

 exceeding the subtending leaf 24. 



22a. Plants of moist ground, bogs, and shores 23. 



22b. Plants of dry uplands Gerardia, Gerardia aspera. 



23a. Corolla about 25 mm. long Gerardia, Gerardia purpurea. 



23b. Corolla less than 20 mm. long Gerardia, Gerardia paupercnla. 



24a. Stem rough on the angles 25. 



24b. Stem glabrous Gerardia, Gerardia tenuifolia. 



25a. Leaves 2 5 mm. wide 



Gerardia, Gerardia tenuifolia var. macrophylla. 

 25b. Leaves thread-like, 1 mm. wide or less 



Gerardia, Gerardia skinneriana. 



26a. Corolla 16 mm. long, or shorter 27. 

 26b. Corolla 20 mm. long, or longer 32. 



27a. Corolla dull-purple, brown, or greenish; one sterile stamen pres- 

 ent (1 2.5 m. high; flowers in summer) (Figwort) 28. 

 27b. Corolla blue or white (14 dm. high) 29. 



28a. Sterile stamen purple Fig-wort, Scrophularia marilandica. 



28b. Sterile stamen yellow Figwort, Serophularia leporella. 



