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172, The Trees of Great Britain and Ireland
with the scale, its apex appears on the upper part of the scar as a minute reflexed
point. Some of the scales are sterile; the others bear each two erect unequally
three-angled seeds.
Taxodium is readily distinguishable in winter from other deciduous trees by the
peculiar buds and branchlet scars which mark the twigs. The latter are very
slender, terete, glabrous, and brown in colour, and bear at their apex the two
pseudo-terminal buds described above, one of which, however, is often aborted in
trees growing in England. Scattered over the twigs appear the branchlet scars and
the lateral buds. The former are small circular depressions, surrounded by a
slightly raised rim, and having a single dot or a minute protuberance in their
centre. The lateral buds, also previously described, are smaller than the branchlet
scars, and on twigs of one year arise just above the minute scars left by the primary
leaves, in which a single dot may be made out with difficulty. Single-dotted
leaf-scars occur in Larix and Pseudolarix; but in these genera branchlet scars
are absent, and the twigs show spurs or short shoots, which are wanting in
Taxodium.
The genus Taxodium was once common and widely distributed over the
Holarctic region. During Miocene and Pliocene times it was spread over the
interior of North America, throughout Europe, and in north-eastern Siberia. In
the present day it is restricted to the Southern United States and Mexico.
The genus can only be confounded with Glyptostrobus, now represented by one
living species, G. heterophyllus, Endlicher,1 a native of the province of Canton, in
Southern China, where it occurs as a small tree along the banks of rivers and
streams. Like Taxodium, it has deciduous foliage and branchlets. The leaves
assume two forms on ordinary branchlets long and linear and arranged in three
rows, on fruiting branchlets closely imbricated, scale-like, concave internally and
carinate externally. The cone, pyriform in shape, is composed of scales, which are
not peltate, but elongated and arising from its base. The bract coalesces with the
scale below; but above the middle is free and recurved, leaving bare the 5 to 7 lobed
summit of the scale. The seeds, oblong or obovate, often short-spurred at the base,
are narrowly winged on the sides and prolonged at the base into a flat, lancet-shaped
wing. Glyptostrobus heterophyllus is not hardy at Kew, where specimens may be
seen in the temperate house. A plant of it is reported to be growing in the open
air at Castlewellan.
1 Glyptostrobus heterophyllus, Endlicher, Syn. Conif. 70 (1847); Masters, Jour. Bot. 1 900, p. 37, and Card. Chron.
xxvi. 489 (1899); Thuya fensilis, Staunton, Embassy to China, ii. 436 (1798); Lambert, Pinus, ed. 2, ii. 115, f. 51.
Taxodium
TAXODIUM DISTICHUM, DECIDUOUS CYPRESS
Taxodium distichum, Richard, Ann. Mus. Par. xvi. 298 (1810); Loudon, Arb. et Friit. Brit. iv.
2481 (1838); Sargent, Silva N. America, x . 151, t. 537 (1896); Kent, in Veitch's Man.
Coniferce, 2 81 (1900).
Cupressus disticha, Linnaeus, Sp. PI. 1 003 (1753).
Schubertia disticha, M irbel, Mem. Mus. Par. xiii. 75 (1825).
Three well-marked forms of Taxodium occur in the wild state, which differ in
certain characters, such as the form of the foliage, its partial persistence or complete
deciduousness, and the time of flowering; and in the present state of our knowledge
these may be considered as constituting one species, the peculiarities mentioned
appearing to depend on conditions of soil and climate, and to be by no means
constant.
1. Var. typica. A tall tree, with a gradually tapering stem, which has an
enlarged base, usually hollow internally and buttressed externally. When
young it is strictly pyramidal in form; but in older trees the crown becomes
wide and flattened, often roo feet across, according to Sargent. The bark
is dull reddish brown, r to 2 inches thick, fissured and separating into long
fibrous scales. The leaves in this form are arranged pseudo-distichously on
horizontally spreading branchlets, and are linear in shape (see generic description).
This form is the one which occurs generally in the alluvial swamps of the south
eastern United States.
2. Var. imbricaria.
Ta\odium distichwm, var. imbricaria, Sargent, I.e. 1 52.
Taxodium distichum pendulum, Carriere, Conif. 1 82 (1867).
Taxodium imbricarium, Harper, Bull. Torrey Bot. Club, xxix. 383 (1902), and xxxii. 105 (1905).
Taxodium sinense, Gordon, Piiietum, 309 (1858).
Ciipressus disticha, fi imbricaria, Nuttall, Gen. ii. 224 (1818).
Glyptostrobus pendulus, Endlicher, Syn. Conif. 7 1 (1847); Hooker fil., Bot. Mag. t. 5603 (1886).
A tree, generally smaller in size than the type, with branchlets normally erect,
but occasionally somewhat spreading and very rarely pendulous. Leaves appressed
on the branchlets and acicular-acuminate (see generic description).
According to Mohr, 1 this is the " upland Cypress " which occurs on the shallow
ponds of the pine-barrens and in semi-swampy woods on poor sandy soil. He
considers it to be greatly inferior to the typical cypress of the alluvial swamps in
regard to the size and quality of the wood; and states that in the earlier stages of
its growth and on vigorous adventitious shoots it produces leaves of the ordinary
form. It passes readily, according to his observations, into the type, where the
soil conditions are favourable. He considers the peculiarity of the foliage to be an
adaptation to check excessive transpiration during the time of drought when the
sandy soil is laid bare to the sun and the supply of water diminishes.
1 Contrib, U.S. Nat. Herbarium, vi, 117 and 325 (1901),