CONIFERALES (PINACEAE) 



299 



DuCHARTRE (5) and Dangeard (36), the former calling attention 

 to the inconstancy in the number of the cotyledons of polycotyledonous 

 forms, and to the lack of any direct relation between these numbers 

 and the connecting vascular strands. Sachs (27) and Masters 

 (34) opposed this view, and so opinion has long been divided. Hill 

 and De FRAEsnE find that among the Taxaceae 

 and many Cupressineae the cotyledons are 

 definitely two, each (except in podocarps) 

 with a single vascular strand, and the root 

 is diarch from the first. Among the Abie- 

 tineae, in which there are three to many 

 cotyledons, the vascular strand is single and 

 the primary root structure is diarch, triarch, 

 tetrarch, etc., the number of protoxylem 

 poles bearing no obvious relation to the 

 number of cotyledons, and variations oc- 

 curring in the same plant. This lack of 

 relationship between the number of cotyle- 

 donary strands and of root poles was noted 

 by Chauveaud (68), who found in Pinus 

 maritima such combinations as five coty- 

 ledons and a pentarch root, seven cotyledons 

 and a tetrarch root, etc., the cotyledons in 

 general being more numerous than the root 

 poles. The argument further appeals to 

 the occurrence of partially split cotyledons 

 {Cupressus torulosa, Abies sibirica, Pinus 

 montana gallica, Araucaria Cunninghamia) , 

 and to the fact that the cotyledons are often 

 obviously in groups. Cases of transition 

 are also cited, in which the strands are 

 more or less divided, and this is accompanied 

 by division of the cotyledon. As an illustration of this, three entire 

 cotyledons were found in Pinus contorta Murrayana, one of which was 

 much larger than the others and contained two separate strands, the 

 conclusion being that one cotyledon had split into two and the other 

 had remained entire. In the case of the higher numbers of cotyledons, 



370 



Figs. 369, 370. — Cephalo- 

 taxus Fortunei: fig. 369, 

 proembryo stUl within the 

 egg; fig. 370, later stage 

 showing the elongated sus- 

 pensor (i); X 63.— After 

 Strasburger (25). 



