526 
Notes. 
This abnormality appears to be of considerable interest in connexion with 
recent discussions 1 concerning the morphology of the synangium-bearing organ in 
the Psilotaceae. There seem to be two possible views as to the nature of the stalked 
cluster of synangia. It may be looked upon as equivalent to one of the normal 
aerial branches of Psilotum , which has for some reason become abortive in develop- 
ment ; on the other hand, it may be regarded as derived from a single proliferated 
synangium-bearing appendage. The common stalk, arising from the main axis, and 
bearing the cluster of synangia, affords a striking point of difference from the 
ordinary sessile ‘ sporophyll/ but, since in the nearly allied Tmesipteris the synangium- 
bearing organs are stalked, this difficulty does not seem insurmountable. The 
presence of a terminal synangium is of extraordinary interest, and has not, so far as 
I am aware, been yet described in Psilotum (cf. Tmesipteris 2 3 ). The theory that the 
abnormality is equivalent to a single ‘ sporophyll ' appears to me far the more 
probable, especially when considered in the light of similar abnormalities in Tmesi- 
pteris , in which genus ordinary branches do not occur. It is not easy to suppose 
such a structure as this cluster to be of a foliar nature, for it can hardly be described 
as a repeatedly dichotomizing leaf. 8 It is more possible to look upon it as a pro- 
liferated sporangiophore (primitively non-foliar in nature 4 ), bearing several synangia, 
associated with several bracts, and terminated by a synangium at its apex. 
M. G. SYKES. 
Royal Holloway College, London. 
INTERNAL PHLOEM IN MYRISTICA.— In M. fragrans, Houtt., the midrib 
of the lamina of the leaf, which is a direct continuation of the petiole, contains a vascular 
cylinder which is much greater in diameter in the tangential than in the radial direc- 
tion; its dorsal half is arc-shaped, while the ventral half is flat, the xylem of the 
latter is incomplete, two of the phloem-groups composing it being without any xylem, 
while what xylem there is present is much less thick than that belonging to the dorsal 
half of the cylinder. Four angular groups of 77iedullary phloe?n occur, one of which 
is in direct connexion with one of the large phloem-groups of the ventral half of the 
cylinder which has lost its xylem. In the petiole these medullary phloem-groups at 
once tend to pass into the broad medullary rays, which they entirely fill, but one 
group is still left in the pith. At the base of the petiole the cylinder becomes, by the 
passing across of its ventral bundles, an arc of three arched bundles, each of which 
has a medullary phloem-group bending round each of its ends, thus standing half-way 
between pith and normal phloem. Thus, before the leaf-bundles enter the stem , the 
medullary phloem leaves the pith and unites with the ordinary phloe7n of the cylinder . 
In M . glaucescens, Jack., essentially the same structure occurs. 
In the pedu7icle of the fruit of the first-named species it was very interesting to 
find, what one might, in an organ of this nature, a priori expect, a transitional struc- 
1 Scott, D. H., Proc. Roy. Soc., 1897, and Prog. rei. bot., 1907; Thomas, A. P. W„ Proc. 
Roy. Soc., 1902 ; Sykes, M. G., Ann. of Bot., January, 1908. 
2 Sykes, M. G., 1. c. Text-fig. vii, x. 
3 Cf. Abnormalities in Psilotum , referred to by Thomas, 1. c., p. 349. 
1 Sykes, 1. c., p. 82. 
