Flora of North America species comparison

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Tsuga caroliniana

Tsuga mertensiana

Carolina hemlock

mountain hemlock, Patton spruce, pruche de Patton
Habit Trees to 30m; trunk to 2m diam.; crown conic. Trees to 40m; trunk to 1.5m diam.; crown conic.
Bark

brown, scaly and fissured.

charcoal gray to reddish brown, scaly and deeply fissured.
Twigs

light brown, thinly covered with short, dark hairs.

yellow-brown, glabrous to densely pubescent.
Buds

oblong, 2–3mm.

oblong, 3–4mm.
Leaves

10–20mm, mostly spreading in all directions from twigs, flat but slightly revolute;

abaxial surface glaucous, with 2 broad, conspicuous stomatal bands, adaxial surface shiny green;

margins entire.

10–25(–30)mm, mostly spreading in all directions from twigs, curved toward twig apex, thickened centrally along midline, somewhat rounded or 4-angled in cross section, both surfaces glaucous, with ±inconspicuous stomatal bands;

margins entire.
Seed

cones ovoid to oblong, 2.5–4 × 1.5–2.5cm;

scales oblong, 12–18 × 8–12mm, bases clawed, apex rounded.

cones oblong-cylindric, 3–6 × 1.5–3cm;

scales broadly fan-shaped, 8–15 × 8–15mm, apex rounded to pointed.
2n

=24.

=24.

Tsuga caroliniana

Tsuga mertensiana
Habitat Rocky montane slopes Coastal and montane forests to alpine slopes (where it occurs in krummholz form)
Elevation 700–1200m (2300–3900ft) 0–2400m (0–7900ft)
Distribution
from FNA
GA; NC; SC; TN; VA
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; CA; ID; MT; NV; OR; WA; BC
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[BONAP county map]
Discussion

Tsuga caroliniana is valuable as an attractive ornamental; a number of cultivars have been developed. The wood is of little commercial importance because of the combination of mediocre quality and the relative rarity of the species in nature.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

The wood of Tsuga mertensiana is somewhat inferior to that of western hemlock both for building purposes and as pulp. This is a very handsome tree with its branches densely clothed with pale, spreading leaves and is adaptable to a wide variety of climatic conditions.

M.Van Campo-Duplan and H.Gaussen (1948) postulated that this taxon originated by hybridization between Picea and Tsuga. Although this is unlikely, some characteristics such as leaf arrangement and shape, phenolic chemistry, and pollen grain structure lend some support for this hypothesis.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 2. FNA vol. 2.
Parent taxa Pinaceae > Tsuga Pinaceae > Tsuga
Sibling taxa
T. canadensis, T. heterophylla, T. mertensiana
T. canadensis, T. caroliniana, T. heterophylla
Synonyms Pinus mertensiana, Abies hookeriana, Abies pattoniana, Hesperopeuce mertensiana, Hesperopeuce pattoniana, Picea (T.), Pinus hookeriana, Pinus pattoniana, T. crassifolia, T. hookeriana, T. pattoniana var. hookeriana, T.-Picea hookeriana
Name authority Engelmann: Bot. Gaz. 6: 223. (1881) (Bongard) Carrière: Traité Gén. Conif., ed. 2 250. (1867)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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