THE AMERICAN AIIBOR-MT.E. 325 



No. 4. Thuja plicata, Donn, the Nootka Sound Arbor- Vitie. 

 Syn. Thuja Occidentalis plicata, Loudon. 

 „ „ „ compacta. Knight. 



„ „ ,, asplenifolia, Hort. 



„ „ „ robusta, Carriere. 



„ „ Warreana, Booth. 

 „ „ flagelliformis, Hort. 



Leaves, on the adult plants, ovate, blunt-pointed, regularly- 

 imbricated in four rows, quite flat, entire, smooth, shining 

 bright green above, and dull glaucous green below ; those on 

 the upper and under sides of the branches and branchlets 

 having a conspicuous elevated gland on the back rib towards 

 the point, and are much broader and less pointed than the side 

 or marginal ones, which lap over on both sides, and appear 

 shorter, more pointed, and regularly jointed, while those on the 

 young plants are very much pointed, particularly the marginal 

 ones, which appear nearly lanceolate, and extended at the 

 points, decurrent at the base, loosely imbricated, and rarely 

 showing the gland on the back ; but as the plant matures, they 

 gradually develop, and the leaves become ovate, more closely 

 flattened along the stems, blunt-pointed, and the branches more 

 rounded along the edges, jointed, and two-edged. Branches, 

 horizontal, rather short, flattened lengthways, spreading, rather 

 compact, and scattered along the stem, with the smaller or 

 lateral ones alternate, regularly two-rowed, straight, quite flat, 

 and pointing outwards at an acute angle ; branchlets, long, 

 straight, linear, flat, and two-edged, regularly jointed, and en- 

 tirely covered with ovate, blunt- pointed, closely flattened leaves, 

 in opposite pairs, as if plaited, with a row of transparent glands 

 along both sides on the back of the leaves. Cones, small, 

 solitary, nodding, scattered, and ovate-oblong. Scales, elliptic, 

 blunt at the ends, flat, partially furrowed, and mostly six in 

 number, each containing two seeds, inversely heart-shaped, and 

 surrounded by a transparent wing, emarginated at the apex. 



A small tree, resembling the American Arbor- Vitae, thickly 

 clothed with spreading, light green branches, found along the 



