Seedling Structure of Gym no sperms, II. 203 
wise be in the way, dies out. The neighbouring phloem masses (/. 8 and p. 9) 
become obliterated, the protoxylems of 8 and 9 approach, ultimately fuse, 
and, finally, the two resin ducts also effect a junction. The same series of 
changes takes place between the bundles of the sixth and seventh cotyledons. 
The rest of the strands behave normally ; their protoxylems attain the 
exarch position before their entry into the axis, and it only remains for the 
contiguous masses of phloem to fuse in pairs ; thus, there is formed 
a 7-arch root. 
Series B. This seedling behaved in an exactly similar manner as 
regards the details of the transition, excepting for the fact that only two 
cotyledon-traces fused to form one pole of the root'. The number of seed- 
leaves was nine and the root 8-arch. 
Pinns insignis , Dougl. 
Series A. The five cotyledons 1 each had the bifurcated bundle as 
described for P. australis ; the top of the hypocotyl was thus occupied by 
ten groups of phloem elements bounded internally by metaxylem. Between 
each pair of bast bundles a resin duct was situated, on the inner side 
of which the protoxylem occurred. As the centripetal displacement of 
these strands took place, the metaxylem rotated further inwards, and the 
phloem masses fused in pairs, so that a pentarch root-structure quickly 
obtained. 
Series B. Of the eight seed-leaves, all exhibited the divided bundle 
with the exception of one, the strand of which retained its undivided nature 
throughout its whole course. Within the axis, the same phenomena 
occurred as have been described for P. australis. Thus terming the cotyle- 
donary traces a, b, c ... h ; a played a subsidiary part in the formation of 
the root-structure ; b formed one pole of the root ; c and d together formed 
one pole in the same manner as the bundles 6 and 7, and 8 and 9 ol 
P. australis (Diagram 4) ; e , although its protoxylem contributed to form 
one xylem ray of the root, must be considered subsidiary ; f formed one 
pole ; and, finally, g and h showed an unequal bifurcation of the vascular 
elements, and behaved in an exactly similar manner to c and d. 
Pinus contorta, Dough, resembles P. insignis pretty closely, although 
the number of cotyledons is fewer. One plant (Series C) exhibited a very 
unequal bifurcation of one of the seed-leaf bundles; the smaller portion 
eventually died out, and the remaining part, together with the adjoining 
non-bifurcated strand, formed one pole of the root. 
Pinus contorta , var. Murrayana. 
The number of cotyledons varies from three to five. Of 25 seedlings 
examined 2 had three cotyledons (8 per cent.), 18 had four (72 per cent.), 
and 5 had five seed-leaves (20 per cent.). The transition in many 
1 According to Masters (loc. cit.), 6-9. 
