ORDER 106. CERATOPHYLLaCEae. (HORNWORT FAMILY.)

_Aquatic herbs, with whorled finely dissected leaves, and minute axillary and sessile moncious flowers without floral envelopes, but with an 8--12-cleft involucre in place of a calyx, the fertile a simple 1-celled ovary, with a suspended orthotropous ovule, seed filled by a highly developed embryo with a very short radicle, thick oval cotyledons, and a plumule consisting of several nodes and leaves._--Consists only of the genus

1. CERATOPHLLUM. L. HORNWORT.

Sterile flowers of 10--20 stamens, with large sessile anthers. Fruit an achene, beaked with the slender persistent style.--Herbs growing under water, in ponds or slow-flowing streams; the sessile leaves cut into thrice-forked thread-like rigid divisions (whence the name from ???a?, _a horn_, and f?????, _leaf_).

1. C. demersum, L. Fruit smooth, marginless, beaked with a long persistent style, and with a short spine or tubercle at the base on each side.--Var. ECHINaTUM, Gray, has the fruit mostly larger (3" long), rough-pimpled on the sides, the narrowly winged margin spiny-toothed.--Slow streams and ponds, across the continent. (Eu., etc.)

SUBCLa.s.s II. GYMNOSPeRMae.

Pistil represented by an open scale or leaf, or else entirely wanting; the ovules and seeds therefore naked (without a pericarp), and fertilized by the direct application of the pollen. Cotyledons often more than two.

ORDER 107. CONiFERae. (PINE FAMILY.)

_Trees or shrubs, with resinous juice, mostly awl-shaped or needle-shaped entire leaves, and moncious or rarely dicious flowers in catkins or solitary, dest.i.tute of calyx or corolla._ Ovules orthotropous or inverted. Embryo in the axis of the alb.u.men, nearly its length. (Wood dest.i.tute of ducts, composed chiefly of a h.o.m.ogeneous large woody fibre which is marked with circular disks on two sides.)

SUBORDER I. Pinaceae. Fertile flowers in scaly aments becoming cones or berry-like. Ovules 2 or more at the base of each scale. Mostly moncious and evergreen.

Tribe I. ABIETINEae. (PINE FAMILY proper.) Fertile flowers in catkins, consisting of numerous open spirally imbricated carpels in the form of scales, each scale in the axil of a thin persistent bract; in fruit forming a strobile or cone. Ovules 2, adherent to the base of each scale, inverted. Seeds winged. Cotyledons 3--16. Anthers spirally arranged upon the stamineal column, which is subtended by involucral scales. Buds scaly. Leaves scattered (or fascicled in n. 1 and 5), linear to needle-shaped.

[*] Cones maturing the second year, their scales becoming thickened and corky.

1. Pinus. Leaves 2--5 in a cl.u.s.ter, surrounded by a sheath of scarious bud-scales.

[*][*] Cones maturing the first year, their scales remaining thin.

[+] Cones pendulous, their scales persistent; bracts smaller than the scales; leaves jointed upon a prominent persistent base, solitary.

2. Picea. Leaves sessile, keeled on both sides (tetragonal).

3 Tsuga. Leaves petioled, flat.

[+][+] Cones erect; bracts longer than the scales; leaf-scars not prominent.

4. Abies. Scales of the large cone deciduous. Leaves persistent, solitary, keeled beneath.

5. Larix. Scales of the small cone persistent. Leaves mostly fascicled, flat, deciduous.

Tribe II. TAXODIEae. Fertile aments of several spirally arranged imbricated scales, without bracts, becoming a globular woody cone.

Ovules 2 or more at the base of each scale, erect. Leaves linear, alternate; leaf-buds not scaly.

6. Taxodium. Seeds 2 to each scale. Leaves 2-ranked, deciduous.

Tribe III. CUPRESSINEae. Scales of the fertile ament few, decussately opposite or ternate, becoming a small closed cone or sort of drupe.

Ovules 2 or more in their axils, erect. Cotyledons 2 (rarely more).

Leaves decussately opposite or ternate, usually scale-like and adnate, the earlier free and subulate; leaf-buds not scaly.

[*] Moncious; fruit a small cone; leaves opposite and foliage more or less 2-ranked.

7. Chamaecyparis. Cone globose; scales peltate. Seeds 1 or 2, narrowly winged.

8. Thuya. Cone pendulous, oblong, of 8--12 imbricated scales. Seeds 2, 2-winged.

[*][*] Dicious. Fruit berry-like, with bony ovate seeds.

9. Juniperus. Fruit-scales 3--6, coalescent. Foliage not 2-ranked.

SUBORDER II. Taxaceae. (YEW FAMILY.) Flowers dicious, axillary and solitary, the fertile consisting of a naked erect ovule which becomes a bony-coated seed more or less surrounded or enclosed by the enlarged fleshy disk (or scale).

10. Taxus. Leaves linear, scattered. Seed surrounded by a red berry-like cup.

1. PNUS, Tourn. PINE.

Sterile flower at the base of the shoot of the same spring, involucrate by a nearly definite number of scales, consisting of numerous stamens spirally inserted on the axis, with very short filaments and a scale-like connective; anther-cells 2, opening lengthwise. Pollen of 3 united cells, the 2 lateral ones empty. Fertile catkins solitary or aggregated immediately below the terminal bud, or lateral on the young shoot, consisting of imbricated carpellary scales, each in the axil of a persistent bract, bearing a pair of inverted ovules at the base. Fruit a cone formed of the imbricated woody carpellary scales, which are thickened at the apex (except in White Pines), persistent, spreading when ripe and dry; the 2 nut-like seeds partly sunk in excavations at the base of the scale; in separating carrying away a part of its lining as a thin fragile wing. Cotyledons 3--12, linear.--Primary leaves thin and chaff-like, merely bud-scales; from their axils immediately proceed the secondary needle-shaped evergreen leaves, in fascicles of 2 to 5, from slender buds, some thin scarious bud scales sheathing the base of the cl.u.s.ter. Leaves when in pairs semicylindrical, becoming channelled; when more than 2 triangular; their edges in our species serrulate.

Blossoms developed in spring; the cones maturing in the second autumn.

(The cla.s.sical Latin name.)

-- 1. _Leaves 5, each with a single fibro-vascular bundle; sheath loose, deciduous; cones subterminal, their scales but slightly thickened at the end and without p.r.i.c.kle or point; bark smooth except on old trunks._

1. P. Strobus, L. (WHITE PINE.) Tree 75--160 high; leaves very slender, glaucous; sterile flowers oval (4--5" long), with 6--8 involucral scales at base; fertile catkins long-stalked, cylindrical; cones narrow, cylindrical, nodding, often curved (4--6' long); seed smooth; cotyledons 8--10.--Newf. to Penn., along the mountains to Ga., west to Minn. and E. Iowa. Invaluable for its soft, light, white or yellowish wood, in large trees nearly free from resin.

-- 2. _Leaves in twos or threes, each with two fibro-vascular bundles; sheath close; woody scales of the cones thickened at the end and usually spiny-tipped._

[*] _Cones lateral; their scales much thickened at the end; leaves rigid._

[+] _Leaves in threes (rarely in twos in n. 2)._

2. P. Tae'da, L. (LOBLOLLY or OLD-FIELD PINE.) _Leaves long (6--10'), with elongated sheaths_, light green; cones elongated-oblong (3--5' long) and tapering; _scales tipped with a stout incurved spine_.--Wet clay or dry sandy soil, Del. to Fla. near the coast, thence to Tex. and Ark.--A tree 50--150 high; staminate flowers slender, 2' long, with usually 10--13 involucral scales; seeds with 3 strong rough ridges on the under side.

3. P. rigida, Mill. (PITCH PINE.) _Leaves_ (3--5' long) dark green, _from short sheaths_; cones ovoid-conical or ovate (1--3' long), often in cl.u.s.ters; _scales with a short stout recurved p.r.i.c.kle_.--Sandy or barren soil, N. Brunswick to N. Ga., western N. Y. and E. Ky.--A tree 30--80 high, with very rough dark bark and hard resinous wood; sterile flowers shorter; scales 6--8.

[+][+] _Leaves in twos (some in threes in n. 4 and 7)._

4. P. pungens, Michx. f. (TABLE MOUNTAIN PINE.) _Leaves stout, short_ (1--2' long), crowded, bluish, the sheath short (very short on old foliage); cones ovate (3' long), _the scales armed with a strong hooked spine_ (' long).--Alleghany Mts., Penn., to N. C. and Tenn.--A rather small tree (20--60 high); cones long-persistent.

5. P. inops, Ait. (JERSEY or SCRUB PINE.) _Leaves short_ (1--3' long); cones oblong-conical, sometimes curved (2--3' long), the _scales tipped with a straight or recurved awl-shaped p.r.i.c.kle_.--Barrens and sterile hills, Long Island to S. C., mostly near the coast, west through Ky. to S. Ind.--A straggling tree at the east, 15--40 high, with spreading or drooping branchlets; larger westward. Young shoots with a purplish glaucous bloom.

6. P. Banksiana, Lambert. (GRAY or NORTHERN SCRUB PINE.) _Leaves short_ (1' long), _oblique, divergent_; cones conical, oblong, usually curved (1--2' long), smooth, the _scales pointless_.--Barren sandy soil, S.

Maine and N. Vt. to S. Mich., central Minn., and northward. Straggling shrub or low tree.

7. P. mtis, Michx. (YELLOW PINE.) _Leaves_ sometimes in threes, _from long sheaths, slender_ (3--5' long); cones ovate- or oblong-conical (barely 2' long), the _scales with a minute weak p.r.i.c.kle_.--Usually dry or sandy soil, Staten Island to Fla., S. Ind., S. E. Kan. and Tex.--A straight tree, 50--100 high, with dark green leaves more soft and slender than the preceding. The western form has more rigid leaves and more tuberculate and spiny cones.