510 Agnes Arber. — On Structure of A ndroecium in Parnassia. 
The present writer holds that the relationship with the Hypericineae is 
closer than was supposed by Drude, and considers that the affinity between 
Parnassia and the Saxifragaceae has, in recent years, been somewhat 
over-estimated. 
Balfour Laboratory, 
Cambridge. 
December 22, 1912. 
EXPLANATION OF PLATE XXXVI. 
Illustrating Mrs. Arber’s paper on Parnassia. 
All the figures represent sections through the vascular tissue of the stamen of Parnassia 
palustris magnified 450 diameters. The sections are so placed that the centre of the flower would lie 
to the right of the diagram in each case. xy. = xylem ; px. = protoxylem ; cpx. = centripetal xylem ; 
cfx. = centrifugal xylem ; ph. = phloem. 
Fig. 1. Transverse section of filament showing ring-like xylem, with protoxylem attached to 
the inner face of the ring on the dorsal side. The numerous small groups of phloem are arranged 
round the xylem and at some little distance from it. 
Fig. 2. Radial longitudinal section through a bundle such as that shown in Fig. 1. 
Figs. 3, 4, and 5. Transverse sections at different levels of the filament and connective of the 
same stamen. 
Fig. 3. Section to show discontinuous xylem ring. Xylem only represented. 
Fig. 4. Section at a higher level to show centripetal xylem entirely detached from centrifugal 
xylem. 
Fig. 5. Section through the connective to show the xylem complex. 
