18 RAMIFICATION. 



long-leaved Pines, Pinus Coulteri, P. Montezuuuv, etc., the secondary 

 branches are comparatively few. A remarkable instance of sparse ramifi- 

 cation occurs in a variety of the common Spruce Fir, known in gardens 

 as Picea excelsa monstrosa. It is a curious fact, too, that other varieties 

 of the same species, as P. excelsa Cla?ibrasiliana, pygmwa, Gregoryana, 

 have the very opposite tendency ; the trunk and primary branches 

 remaining short, whilst the smaller ones become excessively multiplied. 

 Shoots from adventitious buds on the upper side of primary horizontal 

 branches, and often on those of a lower degree, usually take an upward 

 direction, and in that case the leaves spread from them on all sides, as 

 on the principal axis. 



In a large proportion both of Taxads and Conifers the primary 

 branches ramify laterally only, the secondaries branch in the same way, 

 and likewise the tertiaries and so on. In the Cupressinese this lateral 

 branching is continued to braiichlets of the sixth, seventh and even lower 

 degree ; the primary branch with its system of ramifications has 

 consequently a flattened or fronclose form. In the Abietinese this 

 frondose manner of branching is common throughout Abies except in 

 A. Pinsapo, also Picea, Tsuga, Cedrus, Larix, Abietia (Pseudotsuga), 

 and Laricopsis ; but in some species, as Picea Smithiana, Tsuga 

 Albertiana, Larix europcea pendula, it is obscured by the pendulosity 

 of the lateral growths. Lateral branching is also common throughout 

 the Araucarinese ; in the Taxodinege it occurs in Cryptomeria, Taxodium 

 and Sequoia sempervirens ; among Taxads it is conspicuous in Taxus, 

 Torreya and Cephalotaxus. 



In most of the genera included in the Cupressinese as Thuia, 

 Libocedrus, Cupressus (in part) and some of the tropical genera 

 too tender for the open ground in Great Britain, the smaller 

 branch systems are also flattened or frondose ; * in these cases that 

 is, where the production of braiichlets is in one plane only, the 

 lateral leaves are regularly conduplicate and imbricate, and the 

 branchlets arise from their axils, while the median leaves are flattened 

 and closely appressed to the stem. The position of these frondose 

 braiichlets is either horizontal, slightly ascending or slightly 

 descending, as in Cupressus nutkatensis, C. obtusa, Thuia occidental is, 

 or vertical as in Thuia . orientalis, Libocedrus decurrens and in 

 the fastigiate and globose forms of all the Cupressinese except 

 Juiiiperus. In. Cupressus Lawsoniana and its varieties almost every 

 position occurs. 



"Variations further occur, arising from the degree of ramification, 

 as in bi- tri- quadri -pinnate ramification. In some cases this pinnate 

 mode of branching may take place regularly 011 both sides of the 

 shoot or on one side only, and in the latter case generally on the 

 distal side, or that farthest removed from the axis, often as in Thuia 

 causing a curvature of the braiichlet whose concavity is directed towards 

 the main axis."f 



It is worthy of note that these latest formed groups of braiichlets 

 or branch-systems, whether in the flattened or frondose form, or whether 

 produced from all sides of the younger shoots as in Juiiiperus, fall off 



* An exception occurs in Cupressus thyoides known in gardens as the American White 

 Cedar, and especially in its variety leptodada in which the ultimate branchlets are in 

 corymbiform tufts. 



t Masters in Journ. Linn. Soc. XXVII. 286. 



