CVCADEM. 
A. C Y C A D E ^ 1. 
The Embryo^ enclosed in the large endosperm, possesses two opposite unequal 
cotyledonary^ leaves, which lie with their 
towards their apices. The tendency ol 
the subsequent foliage-leaves to branch is 
sometimes displayed even in these cotyle- 
dons, a rudimentary lamina being formed 
on the larger one, with an indication of 
pinnae (as in Zmnia, Fig. 342 B'). The 
seed germinates when laid in moist earth, 
but only after a considerable interval ; the 
testa splits at the posterior end and allows 
the emission of the primary root, which 
at first grows vigorously downwards, but 
sometimes assumes afterwards a tuberous 
form or produces a system of rather thick 
fibrous roots. According to Fig. 342 C 
borrowed from Schacht, and a more recent 
statement by Reinke, the branching of the 
primary root is laterally monopodial; Mi- 
quel, however, asserts the existence of 
bifurcations of the more slender roots in 
older plants of Cycas glauca and Encepha- 
lartos. According to Reinke and Stras- 
burger, only those lateral roots which 
emerge from the ground branch dichoto- 
mously, probably as a pathological pheno- 
menon. By the elongation of the coty- 
ledons which remain in the endosperm 
inner surfaces face to face, cohering 
Fig. 342.— Germination of Zavtia sph'nlis (after Schacht, 
reduced). B commencement of germination, cf tlie cotyledons 
coherent above their elongated base, one of them having at 
its apex (magnified at B') an indication of a pinnate lamina ; 
C seedling six months old ; sa seed, lu the primary root, b the 
first pinnate leaf, x x rudiments of the adventitious roots which 
afterwards grow upwards. 
^ Miquel, Monographia Cycadearum, 1842. [Ditto, On the Sexual Organs of the Cycadaceae ; 
Journ. of Bot., March and April 1869]. — Karsten, Organogr. Betracht, über Zamia muricata, Berlin 
1857. — Mohl, Bau des Cycadeen-stammes (Vermischt. Schrift, p. 195). — Mettenius, Beiträge zur 
Anatomie der Cycadeen (Abhandl. der königl. Sächs. Gesellsch. der Wissensch, vol. VII, 1861). — 
[W. C. Williamson, Contributions towards the history of Zamia gigas, Trans. I.inn. Soc. vol. XXVI, 
1870. — Carruthers on Fossil Cycadean Stems from the Secondary Rocks of Britain, ibid.'] — On the 
structure of the pollen see Schacht, Jahrb. für wissensch. Bot. vol. II. p. 142 et seq. — Kraus, lieber 
den Bau der Cycadeenfiedern (Jahrb. für wissensch. Bot. vol. IV). — Reinke in Nachrichten der königl. 
Gesellsch. der W^issensch. in Göttingen, 1871, p. 532. — De Bary, Bot. Zeitg. 1870, p. 574, — Juranyi, 
Bau u. Entwickelung des Pollens bei Ceratozaniia (Jahrb. für. wissensch. Bot. vol. VIII. p. 382). — 
lieber Wachsthum und Verzweigung der Wurzeln, Reinke, Morphol. Abhandl. 1873. — [Warming, 
Undersogelser og Belragtninger over Cycaderne, and, Bidrag til Cycadeernes Naturhistorie, in the K. D. 
Vidensk. Selsk. Forhandl. 1877 and 1879; also Bot. Zeitg. 1878.] . 
^ Van Tieghem found in three seedlings, hybrids of Ceratozaniia longifolia ? with Cer. Mexicatia 5, 
only a single sheathing cotyledon, in another two very unequal cotyledons. Two embryos of Zamia 
spiralis had two unequal cotyledons, another had three, and another had only one. (See Van Tieghem 
in the French edition.) 
