The Gymnosperms

1. Probably the ancestors of all trees 2. “Naked Seeds,” usually formed on the scales of a cone3. 4 Divisions within the Kingdom Plantae

• We cover Pinophyta (conifers) and Ginkgophyta (ginkgo)

The Gymnosperms

1. No true flowers2. Reproductive morphology includes male and female cones

1. Male cones are smaller and produce pollen2. Female cones are larger and produce seeds

3. Generally a tree will produce male and female cones

Together, the Gymnosperms and the Angiosperms

comprise the seed plants.

Pinaceae: Genera Native to Delaware

1. Pinus (pine)2. Tsuga (hemlock)

At least some members of these genera are native

Pinaceae (the pine family)

• 10 genera with 200 species• Northern hemisphere• The most important family for timber production• 6 genera are native to the U.S.• Only 2 genera are native to Delaware• All monoecious & wind-pollinated• Woody cones

Pinaceae: Pinus (pines) More than 100 species worldwide, N hemisphere Whorled branches Leaves = needles in fascicles Male cones in spring, produce pollen Female cones develop later and are the “pine cones” we know Important products:

- lumber- pulp and paper- turpentine- Christmas trees- pine nuts

eastern white pine Pinus strobus • 5 needles per fascicle, needles have a bluish tinge• Whorled branches like spokes on a wheel• Dark gray, moderately furrowed bark with vertical ridges• Cones 6” long, cylinder-shaped, with lots of resin• Native only in the Piedmont in Delaware• Inhabits moist, well-drained sites• Intermediate shade tolerance• Commercially valuable

loblolly pine Pinus taeda

• 3 needles per fascicle, 6 to 9” long• Cones <6”, oval, prickly spines• Bark has distinctive texture with small vertical plates• Good self-pruner• Native to SE U.S. including DE Coastal Plain• Found on a variety of habitats, also widely planted• Provides nesting sites for birds, cover for deer & other wildlife• Shade-intolerant pioneer species• The mainstay of Delaware’s timber industry and the primary timber tree of the southeastern U.S.

loblolly pine Pinus taeda

• Regenerated by clearcutting or similar techniques• Wood is used for pulp, paper, lumber, plywood, etc.

Loblolly pine stands in Kent

and Sussex Counties, DE

Virginia pine Pinus virginiana• 2 needles per fascicle that are short and twisted• Cones are more round than loblolly cones• Bark scaly, orange• Usually crooked and poorly formed• Small or medium-sized tree• Native throughout Delaware• Dry sites, shade intolerant• Not commercially important here

pitch pine Pinus rigida• Similar to loblolly, except:

• needles are more stiff• needles grow directly from the trunk in tufts• cones are more round• cones persist on the tree for many years

• Uncommon in Delaware• Shade intolerant• Dry sites (adapted to fire)

Cape Henlopen State ParkNJ Pine Barrens

Japanese black pine Pinus thunbergii • 2 needles per fascicle, about 5 inches long• Cones oval, 3 inches long, not prickly• Bark dark and rough• Native to East Asia• The predominant planted tree in some parts of Sussex County, e.g. North Bethany• Commonly planted throughout Delaware•Affected by pinewood nematode causing a fatal disease• Tolerant of poor sites

Native to Delaware Piedmont (remnant Coastal Plain populations) Evergreen, needles only ½” long, not prickly Cones never more than 1” long Mature bark lightly furrowed, purple when cut Much troubled by hemlock wooly adelgid Native to NE USA, SE Canada, and down the Appalachians Inhabits moist woods Extremely shade-tolerant Some commercial and wildlife value

eastern hemlock Tsuga canadensis

Tsuga canadensis

ginkgo Ginkgo biloba (Ginkgoaceae) • Leaves alternate, deciduous, fan-shaped with deep incision • Palmate venation with many veins• Leaves turn yellow and fall off almost overnight• Fruit a modified cone, like a berry, smells bad• Dioecious• Ornamental

Ginkgo biloba