ENUMERATION OF CONIFERS 281 



rubens,SaTg.). Red S. Fig. 73. Tree to 100 feet tall, with short and slender 

 branches forming a narrow pyramidal head and with red-brown bark; 

 branchlets reddish-brown, pubescent; winter-buds ovoid, acute, the terminal 

 bud at base with subulate pubescent scales: leaves quadrangular, acute or 

 mucronate, dark or bright green, shining, about }4 inch long: flowers 

 purple: cones oblong, 1^-2 inches long, green while young, later light 

 reddish-brown, glossy; scales obovate, rounded and entire or slightly erose 

 at the margin. From Canada to the high mountain peaks of North 

 Carolina. — Introduced to Europe in 1755. Hardy probably as far north 

 as Saskatchewan. It is a handsome tree of narrow-pyramidal habit, but 

 it requires a cool and moist situation and is less drought-enduring than 

 most other species. 



Var. virgata, Rehd., is a sparingly branched form with long and slender 

 branches destitute of branchlets, very similar to P. Abies var. virgata. 



18. P. mariana, BSP. (P. nigra. Link. P. brevifolia. Peck). The native 

 Black S. Tree usually to 20-30 or occasionally to 100 feet tall, with slender 

 often pendulous branches forming a narrow irregular head; bark gray-brown; 

 branclalets brown or yellowish-brown, pubescent: leaves quadrangular, often 

 slightly compressed from above, obtusish, dull dark or bluish-green, bloomy 

 especially on the upper side, M~M inch long, stomatic bands above usually 

 somewhat broader than those beneath: flowers purple: cones oval-oblong, 

 globose-ovoid when open, dark purple while young, later dull grayish-brown, 

 3^2-1 H inches long; scales rounded and finely denticulate at the margin. 

 From Labrador to Alaska and south to Wisconsin and Michigan and in the 

 mountains to West Virginia. — Introduced about 1700 to Europe. Hardy 

 as far north as Labrador and Saskatchewan. Very variable in habit; when 

 growing in swamps, plants only a few feet high may bear cones; usually of 

 rather thin and irregular habit. 



The most ornamental garden form is var. Doumetii, Sudw. (P. nigra 

 Doumetii, Carr.). Doumet S. With ascending crowded branches forming a 

 dense conical pwamid. A similar form, somewhat broader at the base with 

 more light bluish-green foliage, is var. Beissneriana, Rehd. (P. nigra mariana, 

 Beiss.). 



Var. ericoides, Rehd. (P. ericoides. Mast.). A pyramidal, loosely branched 

 bush of slow growth with short, finely pointed, bluish-green leaves; the leading 

 shoots glabrescent towards the apex. 



Var. fastigiata, Rehd. (P. nigra fastigiaia, Carr. Abies nigra pumila. 

 Knight). Pi-RAJiiDAL Black S. A columnar form with ascending branches 

 and short, acute leaves. 



19. P. glauca, Voss (P. canadensis, BSP., not Link. P. alba. Link. P. 

 laxa, Sarg.). White S. Plate XXXVI. Tree to 60 or 70, rarely to 120 feet 

 tall, with ascending branches and usually pendent branchlets; bark grayish, 



