io6 The Ohio Naturalist. [Vol. XIII, No. 6, 



II. Leaves simple or merely lobed, venation dichotomous or parallel; stems 

 with numerous branches forming a dense crown. 



1. Without dwarf branches; leaves usuallv eUmgated, with parallel 



veins. (Fossil.) Cordaite.^ CORDAITALES. 



2. With thick wart-like dwarf branches; leaves fan-shaped, entire or 



lobed, sometimes deeply divided, deciduous. 

 •GiNKGOE^. GINKGOALES. ginkgoace^. Ginkgo. Maiden-hair-tree. 



Synopsis of the Cycadales. 



1. Megasporophylls (carpels) leaf-like, arranged in a rosette through 

 which the main stem continues its growth; seeds 8 — 4, seldom 2, 

 horizontal or erect; leaflets with a midrib; cortical cauline vascular 

 bundles present, cycadace^. Cycas. 

 II. Megasporophylls (carpels) highly specialized, arranged in lateral 

 cones; seeds 2, inverted; pinnae parallel-or feather-veined, zamiace^. 



1. Cortical cauline vascular bundles present, forming several wood 



zones. MACROZAMIAT.«. 



(1). Leaves simply pinnate. 



a. Carpels pointed. Macrozamia. 



b. Carpels shield-shaped. Encephalartos. 



(2). Leaves doubly pinnate; stem subterranean. Bowenia. 



2. Cortical bundles absent; primary cambium persistent. zamiat^. 



(1). Leaflets feather- veined. Stangeria. 

 (2). Leaflets parallel-veined. 



a. Ovules on a process of the carpel; carpel pointed and 

 leaf-like. Dioon. 



b. Ovules sessile; carpels shield-like. 



(a). Carpels shield-like, not horned. 



((a)). Tree-like when mature; carpellate cones 2-3 



ft. long. Microzamia. 

 ((b)). Usually with a low tuberous stem or geophi- 

 lous; carpellate cones much smaller. Zamia 

 (b). Carpels 2-horned. Ceratozamia. 



Synopsis of the Strobilophyta. 



I. No vessels (enlarged tracheids) in the secondary wood; wood frequently 

 with resin ducts; cotyledons 2-15. Conifer.^. 



1. Carpels usually numerous, in strobili (cones); seeds covered by the 



carpel tips or by ovuliferous scales; cones rarely becoming fleshy 

 when mature; seeds dry, the testa woody or leathery. FINALES. 

 (1). Leaves spirally arranged. 



a. Pollen wingless; carpels with one to several seeds; ovu- 



liferous scale not prominent, or none. 



(a). Carpel with one seed; microsporangia 5-8, free and 



pendulous. araucariace/E. 

 (b). Carpel with two to nine seeds; microsporangia 2-5. 



taxodiace^. 



b. Pollen grains winged; carpels with two inverted seeds; 

 ovuliferous scales prominent; plants monecious. 



pinace^. 

 (2). Leaves opposite or whorled. juniperace.-e. 



2. Carpels of the cone few or 1; seeds with fleshy testa or covered by a 



fleshy aril. TAXALES. 

 (1). Stamens with 2 microsporangia; pollen winged; seed 1. 



a. Not with phylloclades. podocarpace^. 



b. With phylloclades. phyllocladace^. Phyllocladus. 

 (2). Stamens with 3-8 microsporangia, seeds 1 or 2, erect, pollen 



wingless, taxace^. 



