14 
TREES. 
Simple. 
. Leaves on slender deciduous twigs. Taxodium. 
Leaves clustered on short stout spurs. 42. 
. Scales of cone persistent. Larix. 
Scales of cone deciduous. Pseudolarix. 
. Leaves fan-shaped, veined from the base. Ginkgo. 
Leaves not fan-shaped, netted-veined. 41. 
. Leaves simple. 45. 
Leaves compound. 88. 
. Stipule-scars encircling the twigs: buds net sharp. 46. 
Stipule-scars short, or else buds pungent. 40, 
. Leaves entire: sap not milky. Magnolia. 
Leaves lobed. 47. 
. Buds flattened or 2-edged: sap not millcy.. Liriodendron. 
Buds not flattened. 48. 
. Sap not milky: buds fluted. Platanus. 
Sap milky: buds not fluted. Ficus. 
. Buds with a single scale, in front. Salix. 
Buds naked or with several scales. 50. 
. Buds fusiform, hard, very long and sprcad:ng. Fagus. 
Buds not long and spreading. 51. 
. Mucilaginous and aromatic: twigs green. Sassafras. 
Silvery- or brown-scurfy. Elaeagnus. 
Not scurfy or very mucilaginous. 52. 
. Leaves 2-ranked, at least on spreading branches. 53. 
Leaves in more than 2 ranks. 67. 
. Leaves palmately nerved. 54. 
Leaves pinnately veined. 58. 
. Sap milky: hairs not star-shaped. 55. 
Sap neither milky nor flowing freely. 56. 
. Twigs and leaves hairy. Broussonetia. 
At most downy or velvety or rough. Morus. 
. Twigs moderate: pith continuous. 57. 
Twigs very slender: pith often chambered. Celtis. 
. Leaves entire, glabrate. Cercis. 
Leaves serrate: sometimes with stellate hairs. Tilia. 
