GROUP E: Leaves simple, opposite, over 4.5 mm across.
KEY TO GENERA
1. Leaf blade succulent, columnar or nearly so, to ca 5 mm across ............................................ Batis
1. Leaf blade not succulent, or rarely somewhat so; blades flattened, much broader …….. 2
2. Main stems mostly creeping or trailing, often with upright or decumbent branches; AND/OR plant generally under 40 cm tall with breadth greater than height (some species may also climb by aerial roots) ...........................….3
3. Leaf blade narrowly dissected .................................................................... Glandularia
3. Leaf blade not dissected .......................................................................................... 4
4. Leaf blade crenate to serrate ........................................................................... 5
5. Internodes of thinner twigs 4-angled or -ridged ......................................... 6
6. Leaf blade with veins connecting lateral veins indistinctly and producing no ladderlike pattern, surface smooth or nearly so; petiole (1.1)2-3 mm ...................... Euonymous
6. Leaf blade with veins connecting lateral veins forming a ladderlike pattern, upperside upbulged between these veins; petiole (2)3-12 mm ..........….. Lantana
5. Internodes of all twigs terete or nearly so ................................................. 7
7. Leaves deciduous .......................................................... Decumaria
7. Leaves evergreen .......................................................................... 8
8. Leaf blade apex obtuse to rounded ............................. Linnaea
8. Leaf blade apex acute (See GROUP H) ................... Chimaphila
4. Leaf blade entire ............................................................................................. 9
9. Leaf blade 3-8 mm across ..................................................................... 10
10. Leaf blade with glandular dots; petals yellow, stamens more than 10 …… Hypericum
10. Leaf blade lacking glandular dots; petals white sometimes tinged with pink; stamens 10 (See GROUP H) ............................................................ Leiophyllum
9. Leaf blade mostly over 8 mm across ..................................................... 11
11. Leaves sessile ....................................................................... Phlox
11. Leaves petioled ........................................................................... 12
12. Leaf blade mostly with 5-10 teeth on each edge ......................................................... Decumeria
12. Leaf blade with entire margin ............................................... 13
13. Stipules mostly 10-15 mm, elongate, meeting over bases of petioles at each node, soon breaking near base, falling, and leaving a fringe of stipular remains between and over bases of petioles ................ Psychotria
13. Stipules to ca 1.6 X 2.5 mm, triangular and with tapered apex, attached between bases of petioles at each node, not meeting, eventually falling and leaving a scar only between petiole bases ..................... Mitchella
2. Main stems erect to spreading, strongly arching, and/or ascending; plants usually taller than broad ................…14
14. Leaf blade with more than one principal vein from base .................................................... 15
15. Bundle scars in leaf scars 5 .................................................................. Clerodendrum
15. Bundle scars in leaf scars 3 or not evident (in Phorodendron ) ................................... 16
16. Sharp thorn on end of some lateral twigs and/or spurs ..................................................... Rhamnus
16. Sharp thorn lacking on end of lateral twigs and spurs ...................................... 17
17. Plants partially parasitic on aboveground parts of other woody plants ….......... Phorodendron
17. Plants not parasitic on aboveground parts of other woody plants ........... 18
18. End bud an axillary one ............................................................... 19
19. Twigs of current year with few to no longitudinal ridges; plants of non-brackish inland habitats ............................... Philadelphus
19. Twigs of current year with many longitudinal ridges; plants of coastal brackish habitats ............................................................................ Iva
18. End bud a terminal one on twigs not bearing flowers or fruits ……20
20. Petiole mostly over 25 mm; fruits 2(3-4) winged samaras ................................. Acer
20. Petiole mostly under 25 mm; fruits capsules or drupes ......... 21
21. Bud scales in one or more pairs persisting at base of year 1 twig ...................... Philadelphus
21. Bud scales lacking at base of year 1 twig .................................................... Viburnum
14. Leaf blade with just one main vein from base of blade ...................................................... 22
22. Margin of all leaf blades entire ................................................................................ 23
23. Leaf blades with small glandular dots on one or both surfaces ........................ 24
24. Axillary buds superposed, at least on vigorous twigs; stamens 1-4 …. Forestiera
24. Axillary buds solitary or collateral; stamens 4-many ................................ 25
25. Petioles present; twigs with a dark tan continuous even-textured pith …. Eugenia
25. Petioles absent or present; year 2 twigs hollow or pith cream, greenish, or light tan ..................26
26. Crushed or bruised leaves without a mintish odor; leaves sessile or nearly so, blade sometimes clasping ............................................... Hypericum
26. Crushed or bruised leaves usually with minty odor; leaves petioled, blade never clasping, petioles very short to 6.5 mm ........................................ 27
27. Longest internodes under 15 mm; primary leaf blades usually under 12 mm ................................................................. Clinopodium
27. Longest internodes over 15 mm; primary leaf blade usually over 15 mm ................... Conradina
23. Leaf blades lacking small glandular dots but may have scattered large raised glandular dots ...............28
28. Buds 4-sided and with overlapping prominently keeled scales; leaf scars raised .............29
29. Basal edges of opposing petioles connected by a rib ............................................... Symphoricarpus
29. Basal edges of opposing petioles not connected by a rib .............................................................. 30
30. Bundle scar over 1/2 width of leaf scar and prominently raised above surface of leaf scar ............................................ Syringa
30. Bundle scar less than 1/2 width of leaf scar and/or not raised above surface ........................31
31. Surface of leaf scars on year 2 twigs ca even with edges of leaf scar or slightly depressed; axillary buds often superposed ....................... Forestiera
31. Surface of leaf scars on year 2 twigs deeply concave; axillary buds 1 ................ Chionanthus
28. Buds lacking 1-3 of the above characteristics, if none lacking then leaf scar not prominently raised ...................................................................... 32
32. Mature twigs of current year 4-angled, narrowly 4-ridged, and/or 4-sided, none strongly arching; internodes mostly prominent; petals united ...................... 33
33. Leaf blades mostly 1-2 cm long; flowers and fruits axillary …… Clinopodium
33. Leaf blades 3-20 cm long; flowers and fruits terminal ............ 34
34. Leaves opposite, none whorled, blade apex long-acuminate; inflorescences nearly cylindrical, tapered to apex ..................... Buddleja
34. .... Leaves opposite and some to many whorled, blade apex acute to short-acuminate or obtuse; inflorescences broad, rounded at summit ........35
35. Leaf blade to ca 6 cm .......................................... Phlox
35. Leaf blade nearly all over 6 cm .......................... Hamelia
32. Mature twigs of current year terete or nearly so, sometimes somewhat 4- or 6-sided with corners well-rounded; internodes prominent or very short; petals separate or united 36
36. Stipules (perhaps stipulelike bud scales in Rhizophora ) attached completely around twig just above petiole bases .............................................. 37
37. Stipules firm, those at each node connected by a firm band, forming a persistent sheath around twig, summit with a hard awlshaped tip ca 0.8-1.8 X 0.5-0.6 mm at base ....................................... Chiococca
37. Stipules membranous, soon falling, summit rounded and sometimes with a membranous tip ........................................... 38
38. Petiole mostly 2.3-3 mm across ..................................................... Rhizophora
38. Petiole mostly 1.3-2 mm across ........................................................ Psychotria
36. Stipules absent or, if present, not encircling twig .................................................................. 39
39. Apicalmost 2 major lateral veins of leaf blade arising beyond ca 2/3 of distance toward its apex (at least in the narrower blades), conspicuously arched so that each vein eventually curves back toward midvein toward summit of blade ........................................ 40
40. Plants with abundant to scanty thorns ................................................................... Rhamnus
40. Plants unarmed ....................................................................................................... Cornus
39. Apicalmost main lateral veins of leaf blade arising well beyond 2/3 way and not arching as above …. 41
41. Petiole with pair of large glands just below leaf blade base .................................... Laguncularia
41. Petiole lacking such glands ............................................................................................. 42
42. Leaves spicy-aromatic when crushed ....................................................... Calycanthus
42. Leaves not spicy-aromatic when crushed ................................................................. 43
43. Branches, or some of them, long-arching, rooting at tips ............................. Decodon
43. Branches not arching and rooting at tips ......................................................... 45
44. Mature leaf blade very tight-felty-hairy beneath ....................................... 47
45. Terminal buds to 4.1 mm .................................................. Avicennia
45. Terminal buds absent ........................................................ Borrichia
44. Mature leaf blade glabrous or, if hairy, not tight-felty; fruits various, not flat pods ............ 46
46. Leaves evergreen, sometimes only on decumbent twigs or nearly all falling in severe winters ........................................................................................ 47
47. Mature terminal buds to ca 12 mm, narrowly lanceoid, with 2 valvate scales Osmanthus
47. Mature terminal buds usually smaller, shaped otherwise, bud scales overlapping or small and indistinct ….48
48. Leaf blade mostly 8 mm wide or less ................. 49
49. Leaf blade stiff leathery; petiole 1-2 mm, basal 1/2 essentially parallel with twig (See GROUP A) ............................................... Leiophyllum
49. Leaf blade pliable, not leathery; sessile or nearly so ............. Phlox
48. Leaf blade mostly over 10 mm wide ................... 50
50. Leaves sessile or nearly so ....................... 51
51. Largest twigs mostly 0.5-1.6 mm across ............... Phlox
51. Largest twigs over 2.2 mm across …. Lonicera
50. Leaves clearly petioled ............................. 52
52. Pith dark tan ........................... Eugenia
52. Pith white, whitish, or off-white ......... 53
53. Lenticels absent on year 2 twigs …. Kalmia
53. Lenticels present on year 2 twigs …. Ligustrum
46. Leaves deciduous ....................................................................... 54
54. Stipules present, attached to stem between opposing petiole bases or a distinct scar connecting the bases .................................................. 55
55. Apex of leaf blade obtuse to broadly acute .............................. Pinckneya
55. Apex of leaf blade acute to acuminate .......................... Cephalanthus
54. Stipules and stipular scars absent between opposing petiole bases ................56
56. Leaves, leaf scars, and axillary buds 2-ranked ................................... Buckleya
56. Leaves, leaf scars, and axillary buds 4-ranked ................................... 57
57. Bundle scars 3 in leaf scars ............................... 58
58. Base of year 1 twig lacking persistent bud scales ............... Viburnum
58. Base of year 1 twig with some persistent bud scales ................Lonicera
57. Bundle scar 1 in leaf scars ................................. 59
59. Flowering and fruiting plants much taller than 1.5 m; petioles 2-27 mm ............................................... Ligustrum
59. Flowering and fruiting plants to 1.5 m, usually smaller; petioles 2-3.3(4.2) mm ............................................. 60
60. Leaf scars mostly 0-20 ° with twig; buds superposed in some leaf axils, one bud sometimes minute ............. Nestronia
60. Leaf scars mostly 50-80 ° with twig; buds solitary in leaf axils ................................. Symphoricarpus
22. Margin of at least some leaf blades crenate, serrate, toothed, or lobed ..................... 61
61. Year 2 twigs hollow or nearly so or with diaphragmed pith ............................... 62
62. Leaf blade under 15 mm ...................................................... Stachydeoma
62. Leaf blade 22-170 mm .......................................................................... 63
63. Leaf blade upperside stellate-hairy (10 X magnification may be needed); petals separate .......................................................................................... Deutzia
63. Leaf blade upperside glabrous; petals united ..................................................... Forsythia
61. Year 2 twigs with continuous not diaphragmed pith ......................................... 64
64. Lateral veins of leaf blade ending at a sinus between teeth or branching and and each of the 2, rarely 1, ending at a sinus ….. Lantana
64. Lateral veins ending inside margin or branching and a branch going to a sinus and another to apex of a lobe ..................................................................................... 65
65. Twigs armed with thorns (sometimes quite scattered), prickles, or minutely roughened when rubbed toward apex ...................................................................................... 66
66. Internodes of mature twigs of current year 4-ridged or 4-angled ….. Verbena
66. Internodes of mature twigs of current year terete or nearly so … 67
67. Twigs limber, long branches not self supporting, often supported by other plants, leaves evergreen or semi-evergreen ………………. Sageretia
67. Twigs firm, branches self-supporting, leaves deciduous …............. Rhamnus
65. Twigs lacking thorns and prickles, not minutely roughened when rubbed toward apex ...............68
68. Internodes of mature twigs of current year 4-ridged or 4-angled …...............69
69. Twigs green first year and usually the second; petals separate ........................ Euonymus
69. Twigs becoming grayish or tan to brownish or red by end of first year; petals united ........................................................................ 70
70. Leaf blade mostly 1-3 cm .................... Clinopodium
70. Leaf blade mostly 3-30 cm ................................ 71
71. Surface of leaf blade underside hidden by dense matted hairs except over larger veins ..... Buddleja
71. Surface of leaf blade underside readily evident .......................... Diervilla
68. Internodes of mature twigs of current year terete or nearly so, without longitudinal ribs or ridges .............................. 72
72. Bundle scar 1 in leaf scars ......................................... 73
73. Twigs and bud scales with stellate hairs ................................. . Callicarpa
73. Twigs and bud scales glabrous or with simple hairs ….............74
74. Buds superposed in some leaf axils ......................................... Forestiera
74. Buds solitary in all leaf axils ..................... 75
75. Leaf blade with resinous glands ....................................... Clinopodium
75. Leaf blade lacking resinous glands …… Symphoricarpus
72. Bundle scars in leaf scars 3 (5 or 7) ............................. 76
76. Stipules present on twig and often persistent ..... 77
77. Bud scale 1 (See GROUP F) ................. Salix
77. Bud scales 2 or more ............................... 78
78. Lateral veins of leaf blade nearly straight, each clearly ending in a tooth ................................... Rhodotypos
78. Lateral veins of leaf blade curved and not reaching margin ..................................... Rhamnus
76. Stipules absent, or if present, on petiole ............ 79
79. Leaf blade pinnately lobed ........................................... . Hydrangea
79. Leaf blade palmately lobed or unlobed ..... 80
80. Base of year 1 twigs lacking tightly persistent bud scales .......................... Viburnum
80. Base of year 1 twigs with two or more pairs of bud scales tightly persistent, usually remaining for a few years .........................81
81. Leaf scars with 3, 5, or 7 bundle scars; vascular traces 5-13 in a U-shaped pattern and 1-2 horizontal traces within open half of the U ................... Hydrangea
81. Leaf scars with 3 bundle scars; vascular traces 1, 3, or 5, if 5 then 2 of them a tiny terete trace in each of the upper corners of X-section of petiole ...........................82
82. First or second pair of lateral veins of leaf blade much larger and longer than the others .................... Philadelphus
82. First and second pair of lateral veins of leaf blade smaller than largest ones at midleaf ................................ Diervilla