28 MR. M. T. MASTERS ON THE 
TSUGA. 
The Hemlock Spruces were originally comprised under Pinus. 
Link included them under Picea, others placed them under Abies. 
Carriére established them as a separate genus, in which he was 
followed by Engelmann. The branchlets are marked with the 
slightly prominent pulvini at the base of the leaves, the leaves 
themselves being apparently 2-ranked, mostly uniform in cha- 
racter, with a distinct stalk mostly appressed to the branch, flat, 
with a solitary resin-canal in the centre of the leaf between the 
midrib and the epidermis, and nearly, if not quite, in contact with 
both as in Zorreya. The male flowers are stipitate, axillary, sub- 
globose, and surrounded at the base with small perular scales. 
The anthers have a short spur-like or knob-like projection at the 
base, and open transversely. The pollen-cells are globose. The 
female cones are small, terminal, pendulous, with persistent scales 
and inconspicuous or concealed bracts. The winged seeds are 
very small. The cotyledons are 3-5, linear-oblong, with stomates 
on the upper surface. The primary leaves are similar to the 
cotyledons and alternate with them, but with stomata on the 
lower surface. 
The genus is very nearly allied to Picea, but the habit, the 
leaf-structure, which is quite peculiar, and the floral characters 
combine to constitute a distinct group. By Lemmon and other 
authors the Californian 7. Pattoniana, which differs in the arrange- 
ment of the leaves from the other species, has been made the 
representative of a distinct genus, Hesperopeuke. Van Tieghem 
(Bull. Soc. Bot. France, 1891, p. 414) supports the separation 
on anatomical grounds, showing that the midrib is prominent, 
not sulcate, on the upper surface, the stomates on both surfaces 
instead of on one only, the resin-canal separated from the peri- 
cycle by a few cells instead of being in contact with it as in 
Psuga. Tsuga proper and the section Hesperopeuke have, ac- 
cording to Van Tieghem, a central resin-canal in the pith of the 
root (Bull. Soc. Bot. France, 1891, p. 406). 
The species are distributed in North-western and in North- 
eastern America, the Himalayas, China and Japan. 
Picea, Link. 
This includes the Spruce-firs, which are now, by almost uni- 
versal consent, called by this generic name unless perhaps in 
