P. Cavers. 
225 
L. volnbile and L. scariosum was made possible by the diminution 
in number of the leaf traces consequent on the adoption of a 
subterranean habit by the prothallus and young plant. He considers, 
too, that the well developed sclerotic region of the cortex of these 
three species, a region absent from L. cernuum and feebly developed 
in L. laterale may by enveloping the developing stelar tissues serve 
to insure greater cohesion of the xylem elements into groups and 
bands “ by imparting rigidity and lateral pressure to the tissues.” 
These conjectures, however, as to the causes of the changes supposed 
to have taken place can hardly have the same weight as generali¬ 
sations founded on a comparison with the stelar tissues of other 
members of the Lycopodiales. 
ISABEL M. P. BROWNE. 
LITERATURE QUOTED. 
1. Bower, F. C. “ Phylloglossum Dnimmondi .” Phil. Trans. Roy. Soc., 
Pt. II. Vol. CLXXV, 1885. 
2. Bower, F. C. “ The Origin of a Land Flora.” London, 1908. 
3. Holloway, J. E. “ A Comparative Study of Six New Zealand species 
of Lycopodium." Trans, and Proc. New Zealand Institute, 1909. 
4. Jones, C. E. “ The Morphology and Anatomy of the Stem of the genus 
Lycopodium." Trans. Linn. Soc., Bot. Vol. VII, Pt. II, 1905. 
5. Lang, W. H. ‘‘The Prothallus of Lycopodium clavatum." Annals of 
Botany, 1899. 
6. Petry, L. C. “ A protocorm of Ophioglossum." Bot. Gazette, Vol. LV., 
No. 2, 1913. 
7. Thomas, A. P. W. “ Preliminary Account of the prothallium of 
Phylloglossum." Proc. Roy. Soc., Vol. 69, 1901-2. 
8. Wernham, H. F. “ The Morphology of Phylloglossum Dnimmondi." 
Annals of Botany, 1910. 
9. Wigglesworth, G. ‘‘The young Sporophytes of Lycopodium complanatum 
and Lycopodium clavatum." Annals of Botany, 1907. 
RECENT WORK ON FLAGELLATA AND 
PRIMITIVE ALG^E. 
By F. Cavers. 
(Continued from p. 187j, 
IX.—Conclusion. 
W HILE the recent work summarised here has led, through the 
discovery of interesting new species and genera and the 
re-investigation of forms previously known imperfectly, to a clearer 
knowledge of the Brown Flagellates and of the relations between 
these and the Brown Algae, it has thrown little further light upon the 
phylogeny of the Green Algae. The possibility that the Cryptomonads 
are related to the Chlamydomonads has been discussed by Fritsch 
(46), who admits, however, that the origin of the flagella from a 
depression and the obliquity of the cell in the Cryptomonads is 
against the view of a really close relationship. However, the 
Chrysomonadineae and the lowest Chlamydomonads—the Polyble- 
