Description
Family Pinaceae
Trees
or rarely shrubs
, evergreen
or deciduous, monoecious. Branchlets
often dimorphic
: long branchlets with clearly spirally arranged
, sometimes scalelike leaves; short branchlets often reduced to slow growing lateral
spurs bearing dense clusters
of leaves at apex. Leaves solitary or in bundles of (1 or) 2-5(-8) when basally subtended by a leaf sheath
; leaf blade
linear
or needlelike, not decurrent. Cones unisexual
. Pollen cones solitary or clustered, with numerous
spirally arranged microsporophylls
; microsporophyll with 2 microsporangia; pollen usually 2-saccate (nonsaccate in Cedrus, Larix, Pseudotsuga, and most species of Tsuga) . Seed cones erect
or pendulous, maturing in 1st, 2nd, or occasionally 3rd year, dehiscent
or occasionally indehiscent, with many spirally arranged ovulate
scales
and bracts; ovulate scales usually smaller than bracts at pollination, with 2 upright ovules adaxially, free
or only basally adnate
with bracts, maturing into seed scales. Seed scales appressed, woody or leathery, variable in shape
and size, with 2 seeds adaxially, persistent
or deciduous after cone maturity. Bracts free or adnate basally with seed scales, well developed or rudimentary
, exserted or included
. Seeds terminally winged
(except in some species of Pinus) . Cotyledons 2-18. Germination hypogeal or epigeal. 2n = 24* (almost always) .
Ten or eleven genera and ca.
235 species: N hemisphere; ten genera (two endemic) and 108 species (43 endemic, 24 introduced
) in China.
Species of the Pinaceae are among the most valuable and commercially important plants
in the world. Most species are trees, and are often excellent sources of lumber, wood
products, and resins; many are cultivated for afforestation
and as ornamentals
.Liguo Fu, Nan Li, Thomas S. Elias & Robert R. Mill "Pinaceae". in Flora of China Vol. 4 Page 11. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org.
Genus Tsuga
Trees
evergreen
; crown conic; leading shoot
usually drooping
. Bark
gray to brown, scaly
, often deeply furrowed
. Branches horizontal, often tending to be arranged in flattened "sprays" and arched downward; short (spur) shoots absent; young twigs
and distal portions of stem flexuous
and pendent, roughened by peglike projections persisting after leaves fall
. Buds mostly rounded
at apex, not resinous
. Leaves borne singly, persisting several years, ± 2-ranked or radiating in all directions
, flattened to somewhat angular; abruptly narrowed to a petiolelike base
, set
on peglike projections, these angled
, projected
forward, sheath
absent; apex rounded or notched
; resin canals 1. Cones borne on year-old twigs. Pollen cones solitary, globose
, brown. Seed cones maturing in 1 year, shedding seeds and falling soon thereafter or persisting for several years, pendent, ovoid
, oblong
, or oblong-cylindric, sessile or nearly so; scales
persistent
, shape
various, thin, leathery, lacking apophysis and umbo
; bracts small, included
. Seeds winged
; cotyledons 4--6. x
=12.
Species ca.
10: Northern Hemisphere.
Species of Tsuga are found naturally in areas of relatively moist climates where water stresses are minimal. Most are conspicuous
, if not dominant, members
of the communities in which they occur.
Hemlock wood
is moderately strong
and pliable and lacks resin ducts. With the decline of associated species considered superior in commercial
value, hemlocks have become important in the timber industry
, especially for pulp. Hemlocks are also widely used for horticultural purposes; numerous
cultivars have been developed.Ronald J. Taylor "Tsuga". in Flora of North America Vol. 2. Oxford University Press. Online at EFloras.org.
Taxonomy
- Domain:
Eukaryota
(
)
- Whittaker & Margulis,1978
- Kingdom:
Plantae
(
)
- Haeckel, 1866
- Plants
- Subkingdom:
Viridaeplantae
(
)
- Cavalier-Smith, 1981
- Phylum:
Magnoliophyta
(
)
- Sinnott, 1935 Ex Cavalier-Smith, 1998
- Flowering Plants
- Subphylum:
Euphyllophytina
(
)
- Infraphylum:
Radiatopses
(
)
- Kenrick & Crane, 1997
- Class:
Pinopsida
(
)
- Order:
Pinales
(
)
- Family:
Pinaceae
(
)
- Lindley, 1836, Nom. Cons.
- Pine Family
- Subfamily:
Abietoideae
(
)
- Genus:
Tsuga
(
)
- (Endlicher) Carrière, 185. 1855
- Hemlock [Japanese tsuga, name for native hemlocks of Japan]
- Specific epithet:
brununiana
- (Wall.) Carrière
- Botanical name: - Tsuga brununiana (Wall.) Carrière
- Specific epithet:
brununiana
- (Wall.) Carrière
- Genus:
Tsuga
(
- Subfamily:
Abietoideae
(
- Family:
Pinaceae
(
- Order:
Pinales
(
- Class:
Pinopsida
(
- Infraphylum:
Radiatopses
(
- Subphylum:
Euphyllophytina
(
- Phylum:
Magnoliophyta
(
- Subkingdom:
Viridaeplantae
(
- Kingdom:
Plantae
(
Similar Species
Members of the genus Tsuga
There are approximately 140 species in this genus. Here are just 100 of them:
T. heterophylla · T. canadensis · T. canadensis · T. canadensis · T. blaringhemi · T. brununiana · T. canadensis (Canada Hemlock) · T. canadensis 'Abbott's Dwarf' · T. canadensis 'Abbott's Pygmy' · T. canadensis 'Albospica' · T. canadensis 'Ammerland' · T. canadensis 'Armistice' · T. canadensis 'Arnold Gold Weeper' · T. canadensis 'Atrovirens' · T. canadensis 'Aurea Compacta' · T. canadensis 'Aurea' · T. canadensis 'Bacon Cristate' · T. canadensis 'Baldwin Dwarf Pyramid' · T. canadensis 'Beehive' (Canadian Hemlock) · T. canadensis 'Bennett' (Canadian Hemlock) · T. canadensis 'Betty Rose' · T. canadensis 'Brandley' · T. canadensis 'Branklyn' · T. canadensis 'Cappy's Choice' (Cappy's Choice Canadian Hemlock) · T. canadensis 'Cinnamonea' · T. canadensis 'Coffin' · T. canadensis 'Coles Prostrate' (Cole's Prostrate Canadian Hemlock) · T. canadensis 'Compacta' · T. canadensis 'Coryhill' · T. canadensis 'Creamey' · T. canadensis 'Curley' · T. canadensis 'Curly' (Canada Hemlock) · T. canadensis 'Curtis Ideal' · T. canadensis 'Dawsoniana' · T. canadensis 'Dwarf Whitetip' · T. canadensis 'Essex' · T. canadensis'Everitt Denseleaf' (Everitt Denseleaf Canadian Hemlock) · T. canadensis 'Everitt Golden' (Canada Hemlock) · T. canadensis 'Everitt's Dense Leaf' · T. canadensis 'Everitt's Golden' · T. canadensis 'Fantana' · T. canadensis 'Gentsch White' (Canadian Hemlock) · T. canadensis 'Golden Splendor' (Canadian Hemlock) · T. canadensis 'Gracilis' · T. canadensis 'Greenwood Lake' · T. canadensis 'Horsford Contorted' (Canada Hemlock) · T. canadensis 'Horsford' · T. canadensis 'Horstmann' No 1 · T. canadensis 'Hussii' (Canadian Hemlock) · T. canadensis 'Jacqueline Verkade' · T. canadensis 'Jeddeloh' (Bird's Nest Hemlock) · T. canadensis 'Jervis' · T. canadensis 'Julianne' · T. canadensis 'Kingsville Spreader' · T. canadensis 'Little Joe' · T. canadensis 'Little Snow' · T. canadensis 'Lutea' · T. canadensis 'Many Cones' · T. canadensis 'Minima' · T. canadensis 'Minuta' · T. canadensis 'Monler' (Emerald Fountain® Canadian Hemlock) · T. canadensis 'Nana' · T. canadensis 'New Gold' (Canadian Hemlock) · T. canadensis 'Palomino' · T. canadensis 'Parvifolia' · T. canadensis 'Pendula' (Sargent Hemlock) · T. canadensis 'Pincushion' · T. canadensis 'Popeleski' · T. canadensis 'Prostrata' · T. canadensis 'Pygmaea' · T. canadensis 'Rugg's Washington Dwarf' · T. canadensis 'Sargentii' (Canadian Hemlock) · T. canadensis 'Sherwood Compacta' (Canadian Hemlock) · T. canadensis 'Snowflake' · T. canadensis 'Stewart's Gem' (Canadian Hemlock) · T. canadensis 'Verkade Petite' · T. canadensis 'Verkade Recurved' · T. canadensis 'Von Helms' Dwarf' · T. canadensis 'Warnham' · T. canadensis 'Watnong Star' · T. canadensis f. minuta · T. canadensis f. parvula · T. canadensis f. sparsifolia · T. canadensis var. Bergmans Snowflake (Canada Hemlock) · T. canadensis var. macrophylla · T. canadensis var. minuta · T. canadensis var. sargentii · T. canadensis var. sparsifolia · T. canadiensis · T. caroliniana (Carolina Hemlock) · T. caroliniana 'La Bar Weeping' · T. caroliniana 'Mountain Mist' (Carolina Hemlock) · T. chinensis (Chinese Hemlock) · T. chinensis (Franch.) E.Pritz. var. chinensis · T. chinensis (Franch.) E.Pritz. var. oblongisquamata W.C.Cheng & L.K.Fu · T. chinensis (Franch.) E.Pritz. var. robusta W.C.Cheng & L.K.Fu · T. chinensis forrestii · T. chinensis subsp. forrestii · T. chinensis var. chinensis · T. chinensis var. oblongisquamata
Bibliography
- Krüssmann, G. (1972a): Handbuch der Nadelgehölze, Berlin, Hamburg: Parey
- Cheng Wan-chün, Fu Li-kuo, Law Yu-wu, Fu Shu-hsia, Wang Wen-tsai, Chu Cheng-de, Chao Chi-son & Chen Chia-jui. 1978. Pinaceae. In: Cheng Wan-chün & Fu Li-kuo, eds., Fl. Reipubl. Popularis Sin. 7: 32-281.
- Cheng Wan-chün, Fu Li-kuo, Law Yu-wu, Fu Shu-hsia, Wang Wen-tsai, Chu Cheng-de, Chao Chi-son & Chen Chia-jui. 1978. Pinaceae. In: Cheng Wan-chün & Fu Li-kuo, eds., Fl. Reipubl. Popularis Sin. 7: 32-281.
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Notes
Contributors
- Brands, S.J. (comp.) 1989-2006. Systema Naturae 2000. The Taxonomicon. Universal Taxonomic Services, Amsterdam, The Netherlands. Accessed October 3, 2006.
Identifiers
- Zipcode Zoo Species Identifier: 898696
