35 ° 
CYCADACEAE 
toothed and are usually very rigid and leathery. The nervature is 
important. Three types occur : 
(1) midrib, no lateral nerves : Cycas. 
(2) midrib and lateral nerves : Stangeria. 
(3) numerous parallel or wavy, simple or forked nerves running 
longitudinally : the other genera. 
The firs, are dioecious and usually take the form of cones ; these 
are terminal, and so the stem becomes a sympodium, except in Cycas 
and some species of Encephalartos, &c., where the stem ‘grows 
through’ the fir. or firs. The size of the cones varies consider- 
ably. Each consists essentially of a central axis bearing a number of 
fertile leaves or sporophylls ; occasionally the lowest leaves are sterile 
as in Coniferae. In the <? cone, the leaves (scales) are generally of a 
sort of nail shape (cf. Equisetum), and bear sort upon the lower side. 
Each sorus consists of 2 — 6 sporangia (pollen-sacs), arranged with the 
lines of dehiscence radiating from the common centre. In the $ cone 
the scale (cpl.) is of somewhat similar shape but bears as a rule only 
two sporangia (ovules), whose apices are directed towards the axis of 
the cone. Cycas (q.v.) has no proper cone, but the stem bears a 
whorl of cpls. in place of ordinary leaves. The ovule is of consider- 
able size, orthotropous with one integument. [For details of internal 
structure of ovule, fertilisation, &c., see text-books, and art. Gymno - 
spermae .] The pollen is carried by the wind to the micropyle, where 
it germinates. 
The ovule grows into a large seed; the testa is two-layered, the 
inner layer woody, the outer fleshy. There is also an endopleura on 
the seed. The nucellus is reduced to a thin cap on the top of the 
seed, the bulk of which consists of endosperm, with a straight embryo 
in the centre. There are 2 cotyledons, usually united at the tips. 
The C. are exclusively trop. and subtrop. Of the genera, 4, 7, 8, 
9 (see below) are from Am., 3 and 6 Austr., 2 and 5 Afr., whilst 
Cycas is found in E. Ind., Austr., and the islands of Ind. and Pacif. 
Oceans. 
Classification and Genera. 
I. Cycadeae (cpls. with 8 — 4, rarely 2 ovules; stem growing 
through the ? flr. ; leaflet with midrib only) : 1 . Cycas. 
II. Zamieae (ovules 2; stem not growing through): 2. Stangeria 
(pinna pinnately nerved) ; 3. Bowenia (leaf bipinnate) ; 4. Dioon; 
5. Encephalartos; 6. Macrozamia; 7. Zamia; 8. Ceratozamia; 
9. Microcycas. 
[The above account of the order is abridged from that of Eichler 
in Nat . PJl .] 
Cycas Linn. Cycadaceae. 16 sp. trop. E. Ind., Austr., Polynes. For 
genus characters &c., see order. The female plant does not bear a 
cone, but bears a whorl of cpls. of a woolly brown appearance ; in 
notches upon the margins of these are the naked ovules, usually 4 — 8 
