GROUP IV. PHANEROGAMIA : GYMNOSPERMJ] : CONIFERS. 



483 



ally divided into the two sub-orders, Pinoideas and Taxoideee, based upon tbe 

 structure of the macrosporaugiate flower ; each of these sub-orders includes 

 several families. 



Sub-order I. PINOIDE^E. The macrosporangiate flowers are cones ; the seed 

 has a woody or leathery testa, is enclosed between the macros porophy 11s or 

 the placental scales, and has no aril. 



Fam. 1. Araucarinea : usually dioe- 

 cious ; macrosporophyll simple, bearing 

 a single macrosporangium. The micro- 

 sporophyll bears 5 to 15 free microspor- 

 angia ; microspores without expansions 

 of the exine ; all leaves arranged 

 spirally ; cotyledons 2-4. 



This family includes the two genera, 

 Agathis (Dammara) and Araucaria. 

 Agathis inhabits the Malayan islands, 

 parts of Australia, New Zealand, Fiji 

 Islands ; A. australis is the Kauri 

 Gum-tree : Araucaria inhabits South 

 America (A. brasiliana, Brazil; A. im- 

 bricata, Chili), and Australasia (A. 

 excelsa, Norfolk Island). 



Fam. 2. Abietineee : monoecious; on 

 . its upper surface at the base, the macro- 

 sporophyll bears a large placental scale 

 on the upper surface of which two in- 

 verted macrosporangia are borne. The 

 ripe seed has two wings derived from 

 tissue of the placental scale ; the micro- 

 sporophyll bears two microsporangia ; 

 microspores usually have expansions of 

 the exine ; all leaves arranged spirally ; 

 cotyledons, more than 2, commonly 5, 

 sometimes as many as 15. 



The most important genera may be 

 distinguished as follows : 



A. No dwarf-shoots ; placental scales 

 flat; seed ripens in one year; stem 

 bears whorled branches. 



1. Fruit-cones erect, falling to 

 pieces when ripe; foliage-leaves 

 flat, cylindrical at the base, and not 

 decurrent ; placental scales about 



the same length as the macrosporophylls 



2. Fruit-cones pendent, falling off entire ; foliage-leaves with 

 decurrent projecting base. 



(a) Leaves 4-angular ; placental scales much longer than the 

 macrosporophylls . Picea. 



FiG. 305. Abies pectinata. A Carpel c, 

 seen from above (ventral surface), show- 

 ing s the placental scale, and sk the two 

 ovules (mag.). B Mature cone (nat. size) ; 

 sp axis ; c carpel ; s enlarged placental 

 scale. C Ripe placental scale (s) isolated, 

 seen from above ; ?a the two seeds, each 

 with a wing (/). (After Sachs.) 



Abies. 



