PINE FAMILY, CONIFERS. 55 



Subkingdom SPERMATOPHYTA. 



SEED-BEARING PLANTS. 



Plants producing seeds which contain an embryo formed of one or more 

 rudimentary leaves (cotyledons), a stem (hypocotyl, radicle), and a terminal 

 bud (plumule), or these parts sometimes undifferentiated before germination. 

 Microspores (pollen-grains) are borne in microsporanges (anther-sacs) on the 

 apex or side of a modified leaf (filament). The macrosporanges (ovules) are 

 borne on the face of a flat or inrolled much modified leaf (carpel) and contain 

 one macrospore (embryo-sac) ; this develops the minute female prothallium, an 

 archegone of which is fertilized by means of a tube (pollen-tube), a portion of 

 the male prothallium sprouting from the pollen-grain. 



The Seed-bearing plants form the most numerous group in existence, not less than 120,- 

 000 species being known. The subkingdom was formerly known as Phanerogamia, or Phae- 

 nogamia and more recently as Anthophyta, this term signifying the presence of flowers, 

 which characterizes most of the group. But the consideration that the spore-bearing organs 

 of the Pine Family cannot well be regarded as flowers, and the fact that the production of 

 seeds is the most characteristic difference between these plants and the Pteridophyta, are 

 reasons which have led to the acceptance of the term here adopted. 



There are two classes in the subkingdom, which differ from each other as follows : 

 Ovules and seeds }>orne on the face of a scale ; stigmas none. Class 1. Gymnospermae. 



Ovules and seeds contained in a closed cavity (ovary). Class 2. Angiospermae. 



Class 1. GYMNOSPERMAE. 



Ovules (macrosporanges) naked, not enclosed in an ovary, this represented by 

 a scale or apparently wanting. Pollen-grains (microspores) dividing at maturity 

 into two or more cells, one of which gives rise to the pollen-tube (male prothal- 

 lium), which directly fertilizes an archegone of the nutritive endosperm (female 

 prothallium) in the ovule. 



The Gymnosperms are. an ancient group, first known in Silurian time. They became most 

 numerous in the Triassic age. They are now represented by not more than 500 species of trees 

 and shrubs. 



There are three orders, Coniferales, Cycadales and Gnetales, the first of which is represented 

 in our area by the Pine and Yew Families. 



Family 1. PINACEAE Lindl. Nat. Syst. Ed. 2, 313. 1836. 

 Pine Family. Conifers. 

 Resinous trees or shrubs, mostly with evergreen narrow entire or scale-like 

 leaves, the wood uniform in texture, without tracheae, the tracheids marked by 

 large depressed disks, the pollen-sacs and ovules borne in separate spikes (aments). 

 Perianth none. Stamens several together, subtended by a scale ; filaments more 

 or less united; pollen-sacs (anthers) 2-several-celled, variously dehiscent; pollen- 

 grains often provided with two lateral inflated sacs. Ovules with two integu- 

 ments, orthotropous or amphitropous, borne solitary or several together on the 

 surface of a scale, which is subtended by a bract in most genera. Fruit a cone 

 with numerous, several or few, woody, papery or. fleshy scales ; sometimes berry- 

 like. Seeds wingless or winged. Endosperm fleshy or starchy, copious. Embryo 

 straight, slender. Cotyledons 2 or several. 



About 25 genera and- 240 species of wide distribution, most abundant in temperate regions. 

 Scales of the cone numerous (except in Lari.v) ; leaf-buds scaly. 



Cone-scales woody; leaves needle-shaped, 2-5 in a sheath._ 1. Pinus. 



Cone-scales thin; leaves linear-filiform, scattered _ or fascicled, not in sheaths. 



Leaves fascicled on very short branchlets, deciduous. 2. Lari.r. 

 Leaves scattered, persistent. 



Cones pendulous ; leaves jointed to short persistent sterigmata. 



Leaves tetragonal, sessile. 3. Picea. 



Leaves flat, short-petioled. 4. Tsuga. 



Cones erect ; sterigmata inconspicuous or none. 5, Abies. 

 Scales of the cone few (3-12) ; leaf-buds naked. 



Cone-scales spiral, thick ; leaves deciduous. 6. Taxodium. 

 Cone-scales opposite ; leaves persistent. 



Cone oblong, its scales not peltate. 7. Thuja. 



Cone globose, its scales peltate. 8. Chamaecyparis. 



Fruit fleshy, berry-like, a modified cone. 9. Junipents. 



