496 Agnes Arber . — On the Structure of the Androecium in 
nensis, Fern, et Rydb. ; and P. parviflora, DC. These species all belong, 
according to Drude’s 1 classification, to the same Section ( Nectarodroson ) of 
the genus as our native P. palustris. I have been unable to obtain material 
of representatives of Drude’s other Sections. It is possible, however, that 
P. fimbriata is not very closely related to P. palustris ; Eichinger 2 has 
suggested that, on account of the anomalous form of its nectaries (see 
Text-fig. 2, B, c), it should be removed from the Section Nectarodroson . 
In Parnassia fimbriata the vascular tissue is more highly developed 
than in P. palustris. There is a tendency to the formation of a closed ring 
of xylem and phloem in the peduncle below the flower, instead of three 
detached arcs. In one flower which I examined, the branch of vascular 
tissue, formed to supply each sepal and stamen, also arranged itself into 
a hollow ring almost as soon as it became free from the main vascular ring. 
Text-fig. 2. a, b, c. Parnassia fimbriata , Banks. a, stamen (outer side) ; b, nectary 
(outer side) ; c, nectary (inner side). d, e, f. Parnassia palustris , L. D, stamen (outer side); e, 
nectary (outer side) ; F, nectary (inner side). 
It consisted of internal xylem and external phloem surrounding a patch of 
parenchyma. As it passed outwards it divided into two rings, a small one 
on the axial side, destined for a stamen, and a much larger one, on the 
outer side, destined for a sepal. This large ring entered the midrib of the 
sepal, but, as the lateral veins were given off, it became gradually reduced 
to a single bundle. The ring-structure of the stamen bundle was retained 
throughout the filament as far as the base of the anther. In the connective 
there was a xylem complex, not, however, consisting of so many groups of 
xylem as in P. palustris. We thus see that Parnassia fimbriata shows 
similar peculiarities to P. palustris in the anatomy of the stamen. 
Parnassia montanensis has a slenderer stamen than either of the two 
species just discussed. In accordance with this we find that the vascular 
1 Drude, O. : Ueber die Bluthengestaltung und die Verwandtschaftsverhaltnisse des Genus 
Parnassia. Linnaea, Bd. xxxix, 1875, p. 301. 
2 Eichinger, A. : 1 . c., p. 307. 
