SECT. II 



PHANEROGAMIA 



533 



Family Pinaceae. — This family includes the most imjDortant 

 Coniferae, and on grounds of differences in leaf arrangement and in 

 the position of the ovules is divided into tAvo sub-families. The 

 forms with the leaves opposite or in whorls are included in the 

 Cupressineae ; they also have the ovules erect. Cupressus, Thuja, 

 Juniperus, and Taxodinm are representative genera ; the habit of 

 Taxodium is peculiar. All the forms with alternate leaves are included 

 in the Abieiineae, and, almost Avithout exception, they also possess 



Fig. 503. — Tcvriis iaccota. (A nat. size.) I'o/fiosous. 



inverted ovules. The genera Araucaria and Agatkis — Sequoia and 

 SrAadopitys — Abies, Picea, Larix, and Pinns, may be distributed in 

 three distinct groups Avhich may be named Araucarieae, Sequoieae, 

 and Abietineae, in the narroAv sense. 



Sub-family Cupressineae. — Some of the Cupressineae have needle-shaped leaves 

 in whorls (Juniper, Fig. 504) ; others have decussately arranged, scale-like leaves 

 {Thuja, Junijoerus sahina, Fig. 505). The former type is to be regarded as the 

 more primitive, for the seedlings of Thuja have needle-shaped leaves, and individual 

 branches of scale-leaved forms of Juni2)erus revert to the needle-shaped leaves in 

 whorls of three. The sliort shoots of Taxodium have two ranks of leaves and are 

 shed as a whole. 



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