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TAXUS
Taxus, Linnceus, Gen. PI. 3 12 (1737); Bentham et Hooker, Gen. PI. iii. 431 (1880); Masters,
Jour. Linn. Soc. (J3ot.) xxx. 7 (1893); Pilger, in Engler, Pflanzenreich, iv. 5, Taxacece, n o
EVERGREEN trees or shrubs belonging to the division Taxacese of the order
Coniferse. Bark reddish or reddish brown, thin and scaly. Branches spreading,
giving off branchlets, of one kind only, irregularly alternate, surrounded at their bases
by brownish scales. Buds globular or ovoid, of imbricated scales. Leaves inserted
on the branchlets in a spiral order, on upright shoots spreading radially, on
horizontal shoots disposed by twisting on their petioles in one plane in a pectinate
arrangement, the upper and lower leaves being of the same length, with their dorsal
surfaces turned upwards and their ventral surfaces downwards. In fastigiate varieties
all, or most, of the branchlets assume an erect position, and the leaves in consequence
are arranged radially. The leaves are linear, flat, with recurved margins, dark green
above, paler green below ; the lower surface only bearing stomata, which never form
conspicuous white bands ; narrowed at the base into a short petiole, arising from a
linear cushion on the twig ; mucronate or acute at the apex and without a resin-
canal.
Flowers dioecious, or in rare individuals monoecious, on the under surface of the
branchlets of the preceding year, in the axils of the leaves, the female flowers being
less numerous than the male flowers. Male flowers composed of a stalk, girt at its
base by imbricated scales, and bearing above a globose head of 6-14 stamens with
short filaments. The stamen is expanded above into a peltate connective, which
bears on its lower surface 5 to 9 pollen sacs, united with each other and with the
filament. The female flowering shoot, arising out of the axil of the leaf, is composed
of a number of imbricated scales, in the axil of the uppermost one of which is borne
an ovule, placed so close to the apex of the shoot as to appear terminal ; in the scale
next below a bud occurs, which occasionally develops into a second ovule. The
ovule, which has a small membranous disc at its base, projects out of the scales by
its micropyle. Seed sessile in a fleshy, juicy cup, forming an aril (the enlarged
disc), open at the top and free from the seed in its upper part. The seed variable
in form, 2, 3, or 4-angled, is generally ellipsoid and has a ligneous testa, containing
oily white albumen, in the upper part of which is an axile straight cylindrical minute
embryo with two cotyledons.
Yews differ from all other Coniferse in the character of the fruit. They
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Taxus 99
resemble in foliage certain other genera of Taxacese, but are readily distinguishable
as follows :
Taxus.—Branchlets standing irregularly alternate on the branches. Leaves
stalked, greenish underneath with no definite bands of stomata. Buds composed of
imbricated scales.
Pruminopitys.—Branchlets and leaves as in Taxus, but with valvate bud-scales.
Cephalotaxus.—Branchlets opposite. Leaves like the yew in consistence, but
with white bands beneath showing definite lines of stomata.
Torreya.—Branchlets sub-opposite. Leaves rigid and spine-pointed with white
bands beneath, showing definite lines of stomata.
Saxegotfuza.—Branchlets in whorls, ascending at an angle. Leaves with bases
decurrent on the shoots, and with white bands beneath which are narrow and close
to the median line.
The genus is widely distributed over large parts of North America, Europe,
Algeria, and Asia, and occurs sporadically in the mountains of Sumatra, Celebes,
and the Philippines. Seven distinct species have been described, each confined to a
definite territory. These species are, however, rather geographical forms, only
differing from one another in trivial characters of foliage and habit. The view taken
by Sir Joseph Hooker 1 and by Pilger, the latest monographer of the genus, that
they only constitute one species is probably correct. Many of the supposed specific
distinctions, such as the density of the foliage on the branchlets, the size and form of
the leaf, etc., are due in most instances to the influence of soil, shade, and climate.
Moreover, in the varieties of the common yew, which are known to have arisen as
sports in the wild state or in cultivation, greater differences occur in the characters of
habit, foliage, and fruit, than are observable in the so-called species. In the account
which follows, the geographical forms will be treated as varieties.
1 Himalayan Journals, ii. 25 (1854), and Studenfs Flora of Brit. Islands, 369 (1878).