Hypericaceae

Included in Guttiferae in Michigan Flora. The family is easily recognized by the opposite, entire, punctate leaves (translucent dots ± visible when held to the light, resulting from oil-filled cavities); the inflorescence is cymose, with the terminal flower in each cluster developing first.

1. Petals yellow (occasionally flushed with pinkish), the flowers ordinarily opening; stamens more than 9, or not in distinct groups, without alternating glands; capsules not striate.

Hypericum

1. Petals pink to purple, the flowers rarely open; stamens 9, in 3 distinct groups of 3 each, the groups of basally connate stamens alternating with conspicuous glands; capsules, even when immature, prominently striate longitudinally.

Triadenum

All species found in Hypericaceae

Hypericum adpressumCREEPING ST. JOHN'S-WORT 
Hypericum ascyronGIANT ST. JOHN'S-WORT 
Hypericum borealeNORTHERN ST. JOHN'S-WORT 
Hypericum canadenseCANADIAN ST. JOHN'S-WORT 
Hypericum ellipticumPALE ST. JOHN'S-WORT 
Hypericum gentianoidesORANGE-GRASS 
Hypericum kalmianumKALM'S ST. JOHN'S-WORT 
Hypericum majusLARGER CANADA ST. JOHN'S-WORT 
Hypericum mutilumWEAK ST. JOHN'S-WORT 
Hypericum perforatumKLAMATH WEED, GOATWEED, COMMON ST. JOHN'S-WORT 
Hypericum prolificumSHRUBBY ST. JOHN'S-WORT 
Hypericum punctatumSPOTTED ST. JOHN'S-WORT 
Hypericum sphaerocarpumROUND-FRUITED ST. JOHN'S-WORT 
Hypericum swinkianumSWINK'S ST. JOHN'S-WORT 
Triadenum fraseriMARSH ST. JOHN'S-WORT 
Triadenum virginicumMARSH ST. JOHN'S-WORT 

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. January 22, 2019. https://michiganflora.net/family.aspx?id=Hypericaceae.