222 



THE CULTIVATED EVERGREENS 



terminal on short branchlets; staminate yellow and consisting of 6-12 decus- 

 sate stamens each with 2-4 anther-cells; fertile flowers consisting of 8-12 

 scales in opposite pairs, of which only the middle ones, or in the section Biota 

 the lower ones, are fertile, each scale with 2 ovules inside at the base: cones 

 globose-ovoid to oval-oblong; scales with a thickened ridge or umbo at the 

 apex; seeds 2 or 3 under each scale, thin with broad lateral wings or thick 

 and wingless; cotyledons 2. (Name derived from Greek thya or thyia, a 

 resinous tree.) Also spelled Thuya, Thuia, or Thya. — The genus contains 

 six species in North America and in central and eastern Asia. Except T . 

 sutchuenensis, Franch., from western China, the species are in cultivation and 

 their numerous garden forms are much planted for ornament. 

 A. Branchlets in horizontal planes: cone-scales thin; seeds thin, 

 winged. (Subgenus Euthuja.) 

 B. Leaves of primary axes widely spaced, ending in a long point 

 parallel to the axis, 

 c. Primary axis flattened: leaves conspicuously glandular, 



yellowish- or bluish-green below 1. T. occidentalis 



cc. Primary axis nearly terete: leaves not or inconspicuously 



glandular, usually with whitish markings beneath 2. T. plicata 



BB. Leaves of primary axes close, ending in a short, rigid, spreading 

 point : young branchlets with more or less conspicuous white 

 markings below. 

 c. Under side of leaves slightly or not concave, glandless: 



branchlets thickish, compressed, but scarcely flattened. .3. T. Standishii 

 cc. Under side of leaves concave or grooved below, with con- 

 spicuous white markings, glandular: branchlets much 



flattened 4. T. koraiensis 



AA. Branchlets in vertical planes, bright green on both sides: cone- 

 scales thick; seeds ellipsoidal, wingless. (Subgenus Biota.). . . . 5. T. orientalis 



1. T. occidentalis, L. American 

 Akbor-viTjE. Erroneously but com- 

 monly called White Cedar (which 

 is properly Chamsecyparis). Fig. 45. 

 Tree attaining 60 feet and more, 

 with short horizontal branches 

 ascending at the end and forming 

 a narrow, pyramidal, rather com- 

 pact head; bark light red-brown, 

 shallowly fissured into narrow 

 connected ridges covered with elon- 

 gated scales: leaves ovate, acute, 

 or apiculate, usually glandular, 

 bright green above, yellowish- 

 green beneath, changing in winter 

 45. Thuja occidentalis. usually to dull brownish-green: 



