Syncotyly and Schizocotyly. 805 
possession of two vascular strands in the single seed-leaf giving rise to 
tetrarchy in the root. This type has also been found (with slight modifica- 
tions) in certain Dicotyledons — viz. Eranthis hiemalis 1 and several Cacta- 
ceae. 2 The derivation of this type of structure from the stable tetrarch 
type found in large seedlings seems to have taken place by the crowding 
together of the double bundle and the two lateral bundles of each cotyledon 
into a single median vascular strand, the tetrarchy of the root remaining 
unaltered. 3 If the hypothetical dicotylous ancestors of Anemarrhena had 
such a compressed vascular system we should expect that syncotyly would 
not modify it greatly ; the fact that other tetrarch seedlings show a reduction 
to triarchy through syncotyly cannot be maintained as an argument against 
the structure of the tetrarch Anemarrhena being produced by these means. 
In Helianthus and P minus syncotyly is superposed on a complex cotyle- 
donary vascular system, and reduction follows. In Anemarrhena (as in the 
instructive Leguminous Swainsona Cadelli) simplification of structure had 
occurred prior to syncotyly, and no further reduction is produced by 
fusion. 
A feature of syncotylous anatomy which may be mentioned here is its 
similarity in some respects to the structures produced by longitudinal 
splitting of cotyledons. This parallelism between fusion and fission will be 
further discussed under Schizocotyly (p. 819). 
Finally, there is evidence of the hereditary nature of syncotyly in 
Helianthus animus , of which de Vries 4 cultivated an intermediate race (or 
ever-sporting variety) yielding from 50 to 95 per cent, of syncotyls. It 
appeared probable that similar races could have been isolated from Mercu- 
rialis annua and Centranthus macrosiphon , and also, perhaps, from some 
other species. A pure-breeding syncotylous variety, however, was not 
obtained, even after selection through ten generations. Thus there remains 
some doubt as to whether this teratological syncotyly can be considered as 
a parallel with that which occurs as a normal feature in so many Dico- 
tyledons, and which it is thought gave rise to monocotyly in Anemarrhena 
and its allies. 
Schizocotyly. 
Seedlings with more than two cotyledons are a normal feature in many 
Gymnospermae, and the question as to the primitiveness or the reverse of 
polycotyly has given rise to much discussion. 5 In the Angiosperms the 
phenomenon of polycotyly is extremely rare, being apparently confined to 
1 Sargant (’03). 2 de Frame (TO). 
3 An intermediate condition is very frequent among Leguminosae (Compton (T2 b ) ). 
4 de Vries (’95); (’ll), p. 466. 
5 Duchartre (’48), Dangeard (’92), T. G. Hill and de Fraine (’08-10) taking the view that 
dicotyly is primitive ; Sachs (’82), p. 507, Masters (’91), Dorety (TO) holding the reverse view ; 
Coulter and Chamberlain (TO) considering that 1 the question is an open one ’. 
3 1 
