558 
Notes. 
Lastly, of the several theories thus far proposed to account for 
the occurrence of the abnormalities, none is capable of wide application. 
Sometimes the abnormalities reappear year after year ; sometimes 
they prove inconstant. Had we a fuller knowledge, some explanation, 
partial or complete, might be forthcoming; for frequently, both in 
their distribution in the catkin and on the branch, the changes in sex 
show a tendency to arrangement. At times the male is above the 
female ; at times the reverse is the case. Rarely there are three or 
four belts of flowers on one catkin, male succeeding female, and 
female male, in definite order. 
Royal Gardens, Kew. 
I. H. BURKILL. 
THE AH ATOMY OF THE STEM OF SPECIES OF LYCO- 
PODIUM. — Ten species of Lycopodium have been examined; among 
these two types may be distinguished. 
1. Type of Z. clavatum (L.). The oval stelic arrangement is 
marked by a considerable amount of xylem, broken up into patches 
by bands of phloem. Centrally these bands are strap-shaped, but at 
the ends of the long axes the areas of phloem are external, and occur 
as curved and flattened wedges. Large cells without contents, sieve- 
tubes, appear in the centre of the strap-shaped bands. Protophloems 
and protoxylems are external, forming a continuous ring, as figured 
by Hofmeister ; so that, using De Bary’s terminology, the arrangement 
of the bundles is radial. Pericyclic and the so-called endodermal 
cells occur in concentric zones, 1-3 cells broad. The former swell 
up, especially in glycerine or glycerine-jelly ; the latter are generally 
considerably lignified. The cells of the cortex lying just external to 
the endodermal cells are thickened and lignified, forming a third 
concentric zone several cells deep. To this type conform Z. alpinum 
(L.), Z. Phlegmaria (L.), Z. dendroides (?), and Z. cernuum (L.). 
2. Type of Z. squarrosum. The type which contrasts most 
markedly with the former is found in Z. squarrosum (Forst.), Z. dicho- 
tomum (Jacq.), and Z. nummularifolium (Blume). The phloems occur 
as islands in the sea of xylem, or as inserted peninsulas. The phloems 
are centrally built up, with the apparent sieve-tubes in the centre. 
Protoxylems are well marked, and lie externally, but protophloems are 
not to be distinguished. Endodermal cells and pericycle are found 
as in the previous type. The sclerenchymatous sheath is wanting, or 
very slightly developed. 
