CLUSIACEAE: St. Johnswort Family
KEY TO SPECIES OF HYPERICUM IN GROUP A
(See GROUP E for key to broader-leaved species. )
1. Sepals mostly 2 or 4, occasionally some 5; petals mostly 4 ............................................................. 2
2. Plants with an obvious main stem, usually branching well above ground .................................... 3
3. Longest internode 4.6-8 mm between main leaves; leaf blade 5-12 mm; outer and inner pairs of sepals nearly equal in size; carpels and styles 3 .......................................................................................................... H. microsepalum
3. Longest internode (7.2)10-20.8 mm between main leaves; leaf blade 5-35 mm; outer pair of sepals very much larger than inner; carpels and styles 2 ................................................................................................... H. hypericoides
2. Plants with a main stem not readily evident, low, spreading, or decumbent, branching near the ground....................... 4
4. Longest internode between main leaves (4.8)6-10.2 mm; leaf blade 10-20 mm; pedicel (1)2-2.8 mm, remaining nearly straight in fruit; petals 7-12 mm; fruits ovoid ....................................... H. hypericoides ssp. multicaule
4. Longest internode between main leaves 2.6-6.9 mm; leaf blade 3-10 mm; pedicel (2.6)5-13 mm, reflexed as fruit develops; petals 4-8 mm; fruits oblong-conic ......................................... H. suffruticosum
1. Sepals and petals 5 ....................................................................................................................... 5
5. Leaf blade linear, linear-oblong, or linear-elliptic to narrowly oblanceolate, oblong-ovate, or spatulate ......................6
6. Top of plant bushy-branched; lateral veins usually evident on leaf underside; capsules ovoid-lanceoid; seeds (0.45)0.6-0.8 mm .......................................................................................... H. galioides
6. Top of plant with erect to ascending branches; lateral veins not evident on leaf underside; capsules ovoid, ovoid-conic, ellipsoid, or ellipsoid-oblong; seeds 0.85-1.8 mm .......................................... 7
7. Leaf blade 14-40 X 2.5-3.5 mm; largest sepals to 8 mm across; seeds 1.5-1.8 mm ............... H. dolabriforme
7. Leaf blade 10-90 X 3-10 mm; largest sepals to 2 mm across; seeds 0.85-1.3 mm (See GROUP E)................. H. densiflorum
5. Leaf blade linear-subulate or needlelike .................................................................................... 8
8. Largest leaf blade usually under 11 mm, sepals usually under 5 mm .................................. 9
9. Plants usually bushy-branched from base, often decumbent and matted, rarely over 50 cm; twig internodes 6-angled, especially the thicker ones and just below nodes .................... H. reductum
9. Plants almost always erect, bushy-branched above, to 1.5 m; twig internodes 2-winged, flattened in cross-section, especially the apical ones ................................................ H. brachyphyllum
8. Largest leaf blade usually more than 12 mm, sepals usually more than 5 mm ....................................................... 10
10. Plants with decumbent stems, often forming low mats or at least reclining and straggly; mature capsules narrowly conic with abruptly rounded base ................................................. H. lloydii
10. Plants erect, usually with a single main stem; capsules ellipsoid, ellipsoid-ovoid, or oblong ............................. 11
11. Plants slender, less than 1 m, main stem rarely over 8 mm across; resin glands in leaves and sepals, often darkening upon drying ............................................................................................. H. exile
11. Plants stout, usually to over 1 m, main stem 10-150 mm across at base; resin glands in leaves and sepals usually remaining clear on drying ........................................................... 12
12. Bark about midway of main stem and above smooth, metallic-silvery, exfoliating in large thin curled plates on basal portion of main stem; leaves, sepals, and young stems heavily glaucous ........................... H. lissophloeus
12. Bark about midway of main stem variously roughened, not metallic-silvery, usually exfoliating in irregular strips or flakes; leaves, sepals, and young stems scarcely or not at all glaucous ........................................................ 13
13. Bark on main stem soft and spongy, often becoming 10-20 mm thick near base; leaf blades on main twigs strongly ascending ................................................... H. chapnamii
13. Bark of main stem usually not soft and spongy, less than 10 mm thick; leaf blades on main twigs spreading to only slightly ascending ..............................................................14
14. Bark somewhat spongy-thickened but soon exfoliating in grayish-reddish tissue-thin layers; live leaf blades with a deep longitudinal groove on underside on each side of midrib ...................... H. fasciculatum
14. Bark thin, never spongy, exfoliating in flakes or narrow strips; live leaf blades merely slightly concave on underside on each side of midrib, not grooved .................................................................... H.nitidum