GROUP IV. — PHANEROGAMIA: GYMNOSPERMiE : C0NIFER2E. 



483 



ally divided into the two sub-orders, Pinoideae and Taxoideae, based upon the 

 structure of the macrosporangiate 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 macrosporophylls or 

 the placental scales, and has no aril. 



Fara. 1. Araucarinece : 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. hranliana, Brazil; A. im- 

 bricata, Chili), and Australasia {A. 

 excelsa, Norfolk Island). 



Fam. 2. Abietiiiea : moncecions; on. 

 its upper surface at the base, the macro- 

 sporophj^ll 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 projectiug base. 



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

 macrosporophylls , Picea. 



Fig. 305.— ^J».«« pectinata. A Carpel c, 

 seen from above (ventral surface), ahOWi 

 ing 8 the ])lacental scale, and sk the two 

 ovules (mag.). -B Mature cone (nat. site) } 

 sp axis ; c carpel ; « enlarged placental 

 scale. C Ripe placental scale (8)isolated|- 

 seen from above ; «i the two seeds, each 

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



Abies. 



