April, 1913.] The Classification of Plants, IX. 107 



II. Vessels present in the secondary wood; wood without resin ducts; 

 embryo with 2 cotyledons; strobili in specialized inflorescences; leaves 

 opposite. Gnete.e. 



1. Airchegonia well developed; primary cambium persistent; leaves 



scale-like; stem green and fluted. 



EPHEDRALES. ephedr.\cE/E. Ephedra. 



2. Archegonia reduced; concentric cortical series of vascular bundles 



produced; leaves ribbon-like or broad. GNETALES. 



a. Leaves only 2, ribbon-like and split when old; stem tuber- 

 ous. TUMBOACE.E. Tumboa (Welwitschia). 



b. Leaves numerous, broad, netted-veined. 



GNETACE^. Gnetum. 



Synopsis of the Families of Conifer.^ With More Than One Genus. 



araucariace.e. 



L Seed without a wftig, coalesced with the carpel. Araucaria. 

 2. Seed winged, free from the carpel. Agathis. 



TAXODIACE^. 



I. Dwarf branches; if any, and the leaves not all deciduous at the same 

 time. 



1. Not with true dwarf branches. 



(1). Ovules or seeds 3; carpellate cones often clustered at the 

 end of the twig; leaves rather broad. Cunninghamia. 



(2). Ovules or seeds, 2, or more than 3, if 3 then the carpellate 

 bract toothed; leaves rather narrow or scale-like. 



a. Microsporangia on the stamen 3-6. 



(a). Carpellate bract not toothed. 



((a)). Seeds 2; carpellate cones ^4 in. long. 



Taiwania. 

 ((b)). Seeds 4-9; carpellate cones 1 in. or more in 

 length. Sequoia. 

 (b). Carpellate bract toothed; seeds 3-6. Cryptomeria. 



b. Microsporangia on the stamen 2; carpel with 4-9, mostly 



5 seeds. Arthrotaxis. 



2. Dwarf branches extending into a long double needle; microsporangia 



2, seeds about 7. Sciadopytis. 

 II. Dwarf branches deciduous; carpel shield-like, ovules 2. 



1. Ripe carpels persistent. Taxodium. Bald-cypress. 



2. Ripe carpels deciduous. Glyptostrobus. 



PINACE.E. 



I. Without dwarf branches. 



1. With sterigmata; carpels persistent. 



(1). Carpellate bracts longer than the ovuliferous scales; leaves 



flat. Pseudotsuga. Douglas-fir. 

 (2). Carpellate bracts shorter than the ovuliferous scales. 



a. Leaves prismatic, carpellate cones drooping. 



Picea. Spruce. 



b. Leaves flat. 



(a). Carpellate cones drooping. Tsuga. Hemlock. 

 (b). Carpellate cones erect. Keteleeria. 



2. Without sterigmata, carpels deciduous; carpellate cones erect; 



carpellate bract longer than the ovuliferous scale; leaves mostly 

 flat. Abies. Fir. 



