KEY TO THE GENERA 



EMBRYOPHYTA SIPHONOGAMA 



(PHANEROGAMAE) 



SUBDIVISION GYMNOSPERMAE 



CLASS I. CYCADALES 



FAMILY 1. CYCADACEAE 



Stem simple, rarely branched at the top, woody, with mucilagineous juice. 

 Leaves pinnate or pinnatisect, forming a tuft at the top of the stem and inter- 

 mingled with scales. Flowers solitary, terminal, in the shape of a cone (but 

 sometimes overtopped by the continued growth of the stem), dioecious, without 

 a perianth. Stamens bearing many pollen-sacs on their lower side. Ovules 

 2 — 8 to each carpel, straight, with a single coat. Seeds drupe-hke, albuminous. 

 Embryo with two more or less united cotyledons. — ■ Genera 3, species 25. 

 Tropical and South Afi-ica. (Plate i.) 



1. Stem growing through the female flower, covered with the remains of the 



old leaves. Leaf-segments one-nerved, coiled in bud. Carpels pin- 

 nately toothed or cleft, each with 4—8 ascending ovules. — Species 2, 

 one growing wild in Madagascar and the neighbouring islands, the other 

 cultivated and sometimes naturalized in various parts of Africa. Used 

 as ornamental and medicinal plants ; the fruits are edible and the pith 

 contains starch (sago). [Tribe CYCADEAE.] .... Cycas L. 

 Stem not growing through the female flower. Leaf-segments with several 

 nerves, straight in bud. Carpels each with 2 descending ovules. [Tribe 

 ZAMIEAE.] 2 



2. Leaf-segments with pinnate nerves. Stem without remains of old leaves 



at the base. Cone-scales (stamens and carpels) imbricate.— Species 2. 

 South-east Africa (Natal). Used as ornamental plants. 



Stangeria Th. Moore 

 Leaf-segments with parallel nerves. Stem covered with the remains of 

 old leaves. Cone-scales not imbricate. — Species 20. South and Central 

 Africa. The pith (Kaffir-bread) and the seeds of some species are 

 eaten and also used for making a sort of beer. Several species yield gum 

 or serve as ornamental plants. (Plate i.) Encephalartos Lehm. 



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