AND ANATOMY OF THE STEM OF LYCOPODIUM. 33 
divides, and this process, together with the splitting of the phloem, is repeated until 
the number of protoxylems and protophloems reaches the number shown in the large 
stem. In the early stages there is generally a central xylem-plate, but when the number 
of protoxylems increases to five or six (a) the phloem differentiates in bands reaching 
from one side to the other, or (5) the phloems differentiate as isolated groups which 
break up the continuity of the xylem in the centre. 
4. Subsequently in the branches the number of strands diminishes, and in the ultimate 
branches the reduced structure is similar to that found shortly after the seedling stage. 
5. The disposition of xylem and phloem is constantly altering, not only at the 
periphery, but also throughout the section generally. The length through which a 
definite portion of tissue, such as a phloem-island or phloem-inlet, may be traced, varies 
from about 8 mm. to 1:5 mm. 
6. Branching is monopodial or dichotomous. The former is commonly found in 
creeping species and some erect specimens. The latter occurs frequently in the 
vegetative shoots of epiphytes and just below the strobilar regions of various species. 
7. The sieve-tubes are similar to those found generally in Pteridophyta. 
BIBLIOGRAPHY. 
NAceut, W.— Zeitschrift f. wiss. Botanik, Schleiden und Nägeli, iii., 1846. 
Cramer, C.—Pflanzenphysiologische U ntersuchungen, Nägeli und Cramer, ili., 1855. 
NAcer1, W.—Beitrage z. wiss. Botanik, iv., 1868. 
Sacus, J. v.—Lehrbuch der Botanik, 2 Aufl., 1870. 
HrcErMaArER, F.—Zur Morphologie der Gattung Lycopodium. Bot. Ztg., 1872. 
Russow, E.—Vergl. Untersuchungen über die Leitbündelkryptogamen, 1872. 
SrRAsBuRGER, E.—Die Coniferen und Gnetaceen, 1872. 
Einige Bemerkungen über Lycopodiaceen, 1873. 
Janczewski, E. pEÉ.— Études comparées sur les tubes cribreux. Mém. d. l. Soc. nation. des Sc. 
P 9o uU Pm 
nat. Cherbourg, xxiii., 1881. 
STRASBURGER, E.—Bau und Verrichtungen der Leitungsbahnen. Histologische Beiträge, iii., 
bet 
9 
Davin, E., et L. Wesex.—Etudes sur les Lycopodiacées en general et en part sur L. clavatum. 
Soc. Syndic. des Pharm. d. 1. Côte d'Or, xv., 1896. 
12. Linssaver, L.—Vergleichende Anatomie einiger tropischer Lycopodium- Arten. Sitzungsber. der 
k.-k. Akad. der Wiss. Wien, 1898. 
. Prirzer, E.—Lycopodiacez. Engler u. Prantl, Pflanzenfamilien, i. Teil, 4 Abt., 1900, pp. 563-606. 
. Boonie, L. A.—Note on two Species of Lycopodium. Annals of Botany, xiv. 1900, p. 315. 
