Cambium in Monocotyledons. 89 
able in this country, while suitable material of the few genera, such 
as Cyclantkus and Carludovica, which form the small cohort of the 
Synanthae is also difficult to obtain. 
It is probable that the list of cases of intrafascicular cambium in 
Monocotyledons may eventually be almost indefinitely extended ; 1 the most 
favourable place for detecting the cambium in species where it is ephemeral 
appears to be in the young stems at a very short distance from the growing 
apex, but the young leaves are sometimes equally suitable. 
For comparison with the vestigial cambium of the Monocotyledons 
I have included two drawings (Figs. 3 and 4) showing the young and 
K jh -»-* 
Figs. 3 and 4. Thalictrum flavum, L. Fig. 3. Transverse section of young bundle from an 
inflorescence axis gathered June 1, 1915, in which only protoxylem (flx.) and protophloem (p.ph) 
are fully differentiated. Fig. 4. Transverse section of mature bundle from infructescence axis gathered 
August 23, 1916. x 320 (circa). 
mature bundles of the inflorescence axis of Thalictrum flavum , L. (Ranuncu- 
laceae). The tendency towards a V-shaped xylem, and the fact that 
the cambial activity is chiefly directed to the production of phloem, 
are features which distinctly recall some of the Liliaceae. 
I am indebted for material to Mr. R. I. Lynch, M.A., Curator of 
the Cambridge Botanic Garden, and to Mr. W. Hackett, Assistant Curator 
of the Liverpool Botanic Gardens. I have also to acknowledge a grant for 
laboratory work from the Newnham College Fellowship Committee. 
Balfour Laboratory, Cambridge. 
Septe mber 5, 1917. 
1 That the number of known cases might be much increased by further research has been 
suggested by Salisbury, E. J., Science Progress, vol. xii, pp. 41, 42, 1917. 
