458 



TSUGA. 



tlio other species of Tsuga ; the resin canal is indicated by the 

 letter /, aiid the fibre-vascular bundle of the midrib by /. 

 The essential characters of the flowers and fruits may be thus 

 formulated : 



Flowers monoecious. Staminate flowers in the axils of the uppermost 

 leaves of shoots of the preceding year, small, globose or globose-cylindric, 

 stipitate, and surrounded at the base by numerous small involucral 

 bracts. Anthers with a short spur at the base and dehiscing 

 transversely ; pollen cells globose 



Ovuliferous flowers very small, mostly terminal on lateral branchlets 

 of the preceding year ; bracts shorter than the scales. Cones solitary, 

 pendulous, with persistent scales and inconspicuous enclosed bracts, and 

 ripening the first year. 



Fig 114. Tsuyu Brwnoniana. 1, Staminate. 2, Ovuliferous flower, nat. size. 3, side 4, front view of 



anthers before clehiscence ; 5 and G, after dehiscence x 10 ; 7, pollen grains x 120 ; 



8 back 9, front view of scale and bract. 



The Tsugas thence appear to be made up of characters derived from 

 Abies, Larix and Picea. The leaves are those of an Abies on superficial 

 view, but differ in the presence of only one central resin canal instead of 

 two lateral ones always found in the leaves of Abies ; the cones are 

 those of a Larch with the bract always shorter than the scale ; the wood 

 conforms structurally to that of a Picea. 



Whilst the above characters are common throughout the genus, 

 there is one species Tsuga Mertensiana which differs from the rest 

 in some morphological details observable in the leaves and cones which 

 are of Sufficient value to separate that species sectionally from the 

 others ; the Tsugas therefore admit of a division into two sections 

 thus distinguished : 



EUTSUGA. Leaves flat, obtuse, remotely serrulate at the margins and 

 with stomata on the under side only. Cones small, globose (as broad as 

 long). 



