QNETAGEM. 413 



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

 tant article of food for the Indians. 



S'u}>-Tribe IV. Araticarieip. — Scales of tlie cone spirally arranged, 

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

 spirally arranged. 



Gen. Dammara, Amucaria. Dammara australis is tbe Kauri Pine 

 of New Zealand, vphich attains a heiiiht of 60 metres (800 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, tbe Norfolk Island Pine of the South Pacific Ocean, 

 is 45 to 60 metres high (150-200 f t.),witli horizontal verticitlate branches, 

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

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

 grown for ornamental purposes in California. 



Order Crnetacese. — 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 (pliyl- 

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

 into a tube or column. Tbe 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, tbe inner one, is prolonged beyond the 

 1)ody of tbe ovule into a style-like process, which is occasionally ex- 

 panded above into a stignia-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 ; (3) Epliedra, 

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

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

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



* In Gnetum Onemon. there are three envelopes surrounding the 

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

 trarded as belonging to tbe perianth. Some botanists reject the idea 

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

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

 anth or staminal whorl. This is tbe positinn taken by Parlatore in 

 De CandoUe's " Prodromus ;" by Beccari, in " Nuovo Gioinnle Botan- 

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

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



