58 KEY TO NATURAL ORDERS 
Sus-Division I—GYMNOSPERMAE'—Nakep-Seepep PLANTS 
(Page 81) 
Plants whose seeds are not enclosed in protective seed vessels. There 
are several Classes of Gymnosperms, only one of which is represented 
in our region, though the Ginko tree, which is somewhat extensively 
planted as an ornamental tree, is a member of one of these classes, 
not, however, growing as a native tree with us. Our native plants with 
this peculiarity of naked seeds are all included in a single group. 
CLAss—CONIFERAE—CongeE-BEARING PLANTS 
(Page 81) 
The plants of this class are included in the Pine and Yew families. 
They are trees or shrubs with needle-shaped or scale-like leaves and 
are mostly evergreen. The seeds are borne on the face of a scale, a 
number of scales forming a cone. 
A yast majority of our flowering plants, however, haye their seeds 
concealed in some form of closed envelope as is the case with the pea 
in its pod, the smal] seeds of the larkspur in their dry follicle or the 
seeds of the apple, enclosed by the tough parchment-like walls which 
are themselves surrounded by the pulp, those of the squash covered in 
by the pulp and the tough thick shell. Plants whose seeds are thus 
enclosed constitute the second great Sub-division. 
Suz-Division JI—ANGIOSPERMAE 2—Puants witH EN- 
CLOSED SEEDS 
(Page 89) 
Plants whose ovules or seeds are enclosed in a protective seed ves- 
sel, the ovary. 
This second Sub-division is divided into two classes, each charac- 
terized by the manner of growth of the stem and by the number of 
lobes constituting the seeds. 
Below are seen three figures representing the naked seeds of the Pine 
family and three examples of enclosed seeds. 
Fic. 1, 
1. A scale from the cone of a pine with two winged seeds lying upon its surface. 
2. A cone of hemlock. 3. A single scale from a hemlock cone with its two winged 
seeds. The protection for the ovules thus lying upon the surface of a scale is from 
an overlying scale, the ovule resting between the two, 4. A pod of wild mustard, 
the three lower seeds are exposed by cutting parts of the pod. 5. Three follicles 
of monks-hood, the seeds of one follicle exposed. 6. Section of an apple, showing 
the membraneous core, which constitutes the immediate envelope for the seeds. 
4Gymnos, naked; sperma, seed, 
2 Aggeion, a vessel. 
