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A tree to 75 ft in the wild state (sometimes taller in favoured localities); bark on young trees red, smooth, peeling in thin flakes, on mature trees dark brown, furrowed and fibrous. Leaves closely overlapping and scale-like, pale green to grey-green, more rarely blue-green, acutely pointed, about 1⁄16 in. long; resin-pits usually inconspicuous and inactive. Branchlets irregularly arranged, the final subdivisions four-sided, 1⁄20 in. in diameter. Cones short-stalked, globose, 3⁄4 to 1 in. in diameter, glaucous; scales six (rarely eight), slightly rising towards the middle, where there is a pyramidal, pointed boss.
Native of the S.W. United States and N. Mexico (where it may intergrade with the closely allied C. lusitanica); discovered by Greene in 1880 in S.E. Arizona and also found in S.W. New Mexico. Most of the trees cultivated in Europe as C. arizonica or “var. bonita” belong to the following species, which is a close ally and not recognised by all authorities:
specimens: Borde Hill, Sussex, by Kitchen Garden, 62 × 43⁄4 ft (1978); Exbury, Hants, 65 × 53⁄4 ft (1978); Westonbirt House, Glos., a fine tree, 72 × 51⁄2 ft (1982); Hergest Croft, Heref., in Park Wood, 66 × 51⁄2 ft (1978); Alton Towers, Staffs., 56 × 71⁄2 ft at 1 ft (1974); Stanage Park, Powys, 66 × 6 ft (1980); Mount Usher, C. Wicklow, Eire, 62 × 63⁄4 ft (1975); Avondale, Co. Wicklow, Eire, 82 × 73⁄4 ft (1980).
C. glabra. – This species is distinguished from C. arizonica not only by its grey or silvery glaucous foliage, but also by its blistering and flaking bark, which in its relative is stringy. It is interesting that early this century Elwes and Henry mentioned glaucous-leaved forms of C. arizonica growing in France (Angers and Montpelier) and in Italy (Rovelli’s nursery at Pallanza). These were almost certainly C. glabra, but they knew of no similar trees in Britain. C. glabra is very hardy, and also drought-resistant.
specimens: Royal Horticultural Society’s Garden, Wisley, Surrey, 72 × 51⁄2 ft (1983); Exbury, Hants, 68 × 51⁄4 ft (1978); Stratford Park, Glos., 75 × 41⁄4 ft (1984); Bath Road, Cheltenham, Glos., 56 × 51⁄4 ft (1979); Royal Victoria Park, Bath, 79 × 53⁄4 ft (1984); Henrietta Park, Bath, 68 × 41⁄4 ft (1981); Leighton Hall, Powys, 60 × 51⁄2 ft (1984); Bulkeley Mill, Gwyn., 62 × 71⁄4 ft (1984); Powerscourt, Co. Wicklow, Eire, 80 × 71⁄2 ft (1980).
The clones ‘Conica’ and ‘Pyramidalis’, although similar, are not identical. The latter is somewhat broader than the former, and more silvery glaucous. Of neither has the history been ascertained. The cultivar-name ‘Pyramidalis’ apparently starts in the Hillier catalogue for 1928. The Dutch dendrologist den Ouden mentions ‘Conica’ in a work on conifers published in 1949, but the name was current in the trade (as C. arizonica conica). It was probably first distributed by a French or Italian nursery. To complicate matters, there is also ‘Glauca’, described in 1916 as being of conical habit, with juvenile, glaucous blue foliage.
In Britain, the commonest clone by far is ‘Pyramidalis’, of which the following examples have been recorded: University Botanic Garden, Cambridge, pl. 1937, 50 × 31⁄4 ft (1982); Silwood Park, Berks., 46 × 33⁄4 ft (1982); Brynderwyn, Powys, pl. 1936, 52 × 41⁄2 ft (1977); Cathays Park, Cardiff, 50 × 41⁄2 ft (1980).
Five varieties of Cupressus arizonica are recognised by Farjon (2001, 2005c), though prior to the revision by Little (1966) they were all regarded as separate species. The morphological characters that separate the varieties (bark colour and texture, leaf resin glands and leaf colour, cone serotiny) intergrade and may be the result of ecological factors. For these reasons, Watson & Eckenwalder (1993) employ a conservative taxonomic concept, recognising no varieties. Cupressus arizonica (including vars. arizonica, glabra and stephensonii) was described by Bean (B799, S199) and Krüssmann (K103). Although the species is a commonly grown garden plant, a key to the currently accepted varieties is provided below, adapted from Little (1966). All seem to be hardy and easy to grow wherever C. arizonica can be cultivated.
Bark of mature trees grey or dark brown, rough and furrowed
Bark of mature trees reddish brown, smooth, peeling in thin, curling plates
Cone scales open at maturity;
var. montana (Wiggins) Little
Leaf resin glands conspicuous and active;
var. nevadensis (Abrams) Little
Leaf resin glands absent or inactive, rarely active; Mexico (Chihuahua, Coahuila, Durango, Tamaulipas, Zacatecas) (see B799, K103)
Leaf resin glands inactive or slightly active; seeds usually over
var. stephensonii (C.B. Wolf) Little
Leaf resin glands very active, resulting in white flecks of resin on the foliage; seeds usually 4–5 mm long, glaucous; USA (Arizona:
var. glabra (Sudw.) Little
C. arizonica var. bonita Hort. and of many authors, not Lemm