Class 1. GYMNOSPERMAE . Naked-seeded Plants. 



Ovules naked, inserted on the upper side of an open, mostly 

 flat, more or less developed scale, not enclosed in an ovary. Pollen- 

 grains divide into two or more cells, of which one produces a pollen- 

 tube; this fertilizes the ovule directly. All trees or shrubs, most 

 of them evergreen. 



Family 1. PINACEAE. Pixe Faaiily. 



Resinous trees or shrubs, mostly with evergreen, needle-shaped or linear 

 leaves. Stamens several together, subtended by a scale, forming elongated 

 aments; filaments more or less united; anthers usually 2-celIed; pollen-grains 

 globose, ellipsoid, or lobed. Pistillate aments consisting of usually luimer- 

 ous spirally disposed scales subtended by bracts. Ovules inverted, usually 

 2 at the base of each scale. Fruit a dry cone. Seeds usually 2 at the base 

 of each scale, often samara-like; wing formed by a part of the scale. 



Leaves several together (in one species solitary), surrounded by a sheath at the baie; 



cones maturing the second year. 

 Con&-scales with dorsal, usually spine-armed appendages. 



Seeds with elongated wings attached to the seeds when they fall; leaves mostly 



Math two flbro- vascular bimdles. 1. Pincs. 



Seeds with narrow or rudimentary wings, which remain attached to the scales 

 when the seeds fall ; leaves with a single flbro-vascular bimdle. 



2 Caryopitys 



Cone-scales with inconspicuous terminal unarmed appendages. 



Seeds with rudimentary wings attached to the scalas: cones subsessile, spreading. 



„ , . , 3, APIND3. 



Seeds with well-developed wings, which remain attached to the seeds; cones dis- 

 tinctly stalked, pendulous. 4. Strobus. 

 Leaves not surrounded by sheaths ; cones maturing the first year. 



Leaves in fascicles at the ends of short branches, deciduous. 5. Larix. 



Leaves scattered along the branches, persistent. 



Branches smooth, not roughened by persistent leaf-bases. 



Cones erect, their scales and bracts deciduoas from the persistent axis; leaves 



sessile with circular leaf-scars. 6. ABIES. 



Cones pendulous, their scales and bracts persistent; leaves petioled with trans- 

 versal oval leaf-scars. 7. Pseudotsuga. 



Branches roughened by persistent leaf-bases (sterigmata). 



Leaf-blades petioled with a single dorsal duct; anthers opening transversely; 



seeds with resin- vesicles. 

 Leaves flat, with stomata only on the lower side, 2-ranked by twisting of 



the petioles ; cones small, diooping. 8. Tsuga. 



Leaves not much flattened, keeled on the lower side, with stomata on both 

 sides, spreading in all directions; cones elongated, erect at least at first. 



9. Hesperopeuce. , 



Leaf-blades sessile, with two lateral ducts, in ours 4-angled and spreading in ' 

 all directions; anthers opening longitudinally; seeds without resin-vesicles. 



10. PICEA. 



1. PINUS (Tourn.) L. Hard Fixes, Pitch Pines. 



_ Monoecious evergreen trees or rarely shrubs, with two kinds of leaves, the 

 primary leaves chaff-like, deciduous, the secondary ones green, needle-shaped, 

 usually with two fibro-vascular bundles (in all ours except in P. aristata), in 

 fascicles of 2-5, surrounded by a sheath, which is usually persistent. Staminate 

 aments elongated, at the ends of branches of the preceding year; anthers 2- 

 celled, opening longitudinally; pollen-grains 3-celled, the two lateral cells empty. 

 Pistillate aments globose or oblong, sessile or nearly so, below the terminal bud 

 or on the young twigs. Cones in ours subsessile, matiu-ing the second autumn; 

 scales thick, spreading at maturity, with a dorsal appendage or thickening, 

 usually armed with a spine or at least a tubercle. Seeds samara-like, with the wing 

 remaining attached to the seed. 



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