78 American Midland Naturalist Monograph No. 7 



10. Stems herbaceous throughout, simple or nearly 

 so, from a slender, creeping, stoloniferous 

 base; inflorescence few-flowered; seeds striate; 

 wet ground, rare; Fulton and St. Clair coun- 

 ties.. July-Aug H. ellipticum Hook. 



9. Styles free to base; stigmas ovoid; plants virgate; 



moist woods, rare, Jackson and Pope counties 



H. denticulatuni Walt. 



3. Petals black-lined or black-dotted, at least along the margin; 

 styles separate; capsules 3-loculed. 

 11. Petals dotted only along the margin; leaves linear or 

 oblong, 1-2 cm long, 2-8 mm wide, numerous; stem 

 much branched, often with basal stei'ile shoots; road- 

 sides and fields, common; nat. from Eur. June- Aug. 



Common St. John's-wort H. perforatum L. 



11. Petals marked with black lines and dots; leaves elliptical 

 to ovate. 

 12. Leaves elliptical, obtuse or acute; petals 5-7 mm long; 

 capsules 4-6 mm long; roadsides and open woods. 



July-Aug. Spotted St. John's-wort 



H. punctatum Lam. 



12. Leaves lanceolate or ovate, acuminate; petals 10-15 

 mm long; capsules 6-8 mm long; open woods, local. 



May- June. Large Spotted St. John's-wort 



H. pscudomaculatum Bush 



2. Flowers small, the petals 3-6 mm long; stamens few (5-20) . 

 13. Capsules 3-3.5 mm long; sepals linear, obtusish; leaves oval 

 or elliptical, obtuse, 5-veined from the base; plants often 

 diflfusely branched; moist soil, local. July-Sept. Dwarf 



St. John's-wort H. mutilum L. 



13. Capsules 4-6 mm long; sepals narrowly lanceolate, acumi- 

 nate; branching strict, erect, or stem simple. 

 14. Leaves oval to elliptic-lanceolate, clasping, 3- to 7- 

 veined from the base. 

 15. Leaves firm, ovate, acute, often distant; stem simple; 

 sepals lanceolate, acuminate; wet sandy barrens, 



local H. gynuianthurti Engelm. & Gray 



15. Leaves elliptic-lanceolate, acutish, somewhat rounded 

 at the clasping base, 3-10 mm wide; sepals 5-6 

 mm long, nearly equalling the capsule; moist 

 ground, rare, n.e. 111., extending southwestward to 

 Tazewell Co. July-Aug. Larger Canadian St. 



John's-wort H. rnajus (Gray) Britt. 



14. Leaves lanceolate, obtuse, tapered at the sessile base, 1-3 

 mm wide; sepals 2.5-3 mm long, noticeably shorter 

 than the capsule; moist sandy soil, in the northern half 



of 111. July-Sept. Canadian St. John's-wort 



H. canadense L. 



