GNETACE^S. 413 



liar in its single leaves. Its seeds are large and constitute an impor- 

 tant article of food for the Indians. 



Sub-Tribe IV. Araucarie.<p. Scales of the cone spirally arranged, 

 deciduous. Leaves flat or four-angled, often broad, sub-opposite, or 

 spirally arranged. 



Gen. Dammara, Araucaria. Dammara australis is the Kauri Pine 

 of New Zealand, which attains a heij-ht of 60 metres (200 ft), and is 

 much used for making masts. From D. alba of the Malay Islands 

 Dammar resin is obtained. 



The genus Araucaria contains large pyramidal trees of singular 

 beauty. A. excelsa, the Norfolk Island Pine of the South Pacific Ocean, 

 is 45 to 60 metres high (150-200 ft.),with horizontal verticillate branches, 

 forming a pyramidal head. The timber is valuable. This species 

 and A. imbricata from Chili, and A. Bidwttli, of Australia, are now 

 grown for ornamental purposes in California. 



Order Gnetaceae. The Joint-firs are undershrubs, or small trees, 

 with usually jointed rush-like stems, and opposite setaceous or oval 

 leaves (the exceptional Welwitschia will be described below). The 

 flowers differ from those of the other Gymnosperms in always having a 

 perianth i.e., a floral envelope ; in some cases this is single and bifid, 

 while in others it is composed of two or more bract-like bodies (phyl- 

 lomes). The stamens are single (in Gnetum), or six to eight united 

 into a tube or column. The ovules are single in each flower, and are 

 provided with one or two envelopes ;* in the former case the single 

 integument, and, in the latter, the inner one, is prolonged beyond the 

 body of the ovule into a style-like process, which is occasionally ex- 

 panded above into a stigma-like body. 



The flowers are disposed in the axils of the opposite bracts of short 

 lateral branches (aments or catkins), which spring from the axils of 

 the leaves upon the main stems. 



Three genera of Gnetaceae have been described, viz. : (1) Gnetum, 

 with from fourteen to eighteen species, mostly confined to the East In- 

 dian islands and the tropical portions of South America ; (2) Ephedra, 

 with about as many species, widely distributed in temperate and trop- 

 ical regions (five species occur in the southwestern part of the United 

 States) ; (3) Welwitschia, with but one South African species. 



* In Gnetum Gnemon there are three envelopes surrounding the 

 body of the ovule, but it is probable that the outer one is to be re- 

 garded as belonging to the perianth. Some botanists reject the idea 

 that any of these are proper ovule integuments, and regard the inner 

 one as "a true ovary, and the outer one or two as belonging to the peri- 

 anth or staminal whorl. This is the position taken by Parlatore in 

 De Candolle's " Prodromus ;" by Beccari, in " Nuovo Giornale Botan- 

 ico Italiano," Jan., 1877 (Delia Organogenia, etc., del Gnetum Gnemoit); 

 and by Dr. Gray, in " Bot. Text-Book," 6th ed., 1879, vol. 1, p. 269. 



