2 1 6 Seward. — On Rachiopteris Wil/iamsoni sp. nov 
Marattiaceae when we are dealing with Palaeozoic Ferns, but 
in spite of this there seems little doubt that we must regard 
this new Carboniferous type as more closely connected 
with Marattiaceae on histological grounds than with any 
other family. In the monograph on the Marattiaceae by 
De Vriese and Harting there is a figure of a transverse 
section of an oval vascular bundle of Angiopteris Teysmanniana 1 
( = Angiopteris evecta 2 , var. Teysmanniana) which shows a series 
of £ canals ’ disposed at regular intervals in the phloem ; these 
are described as small canals containing a yellow juice holding 
small globules in suspension. The phloem is spoken of as 
a c gaine cellulaire.’ On examining sections of Angiopteris 
evecta var. Teysmanniana , for which I am indebted to the 
Director of the Royal Gardens, Kew, I find a regular 
arrangement of such elements as are represented by De 
Vriese and Harting ; in longitudinal section they have the 
form of fairly wide tubes with oblique cross- walls, and contain 
a considerable quantity of small yellowish globules. They 
are probably sieve-tubes of a type unusual in Ferns, and not 
canals as described by De Vriese and Harting. Fig. 14 shows 
the large and conspicuous form of these peculiar elements ; 
opposite the protoxylem there is an indication of cell-separation 
(• Liickenparenchym ’ of Russow) such as frequently occurs in 
the fossil bundles. 
The bundle-canals of Rachiopteris Williamsoni cannot be 
regarded as homologous in structure with the large sieve-tubes 
of Angiopteris ; their mature form and their manner of develop- 
ment are strongly suggestive of small secretory canals. In 
the vascular bundles of petioles of Osmunda regalis , we find 
groups of tannin-sacs on the concave side of the curved 
bundle 3 , and to some extent on the convex side ; these may 
1 Monographic des Marattiacees, 1853, p. 24, PI. VII, Fig. 17. 
2 In the Synopsis Filicum, 1868, p. 440, all the species of De Vriese and Harting 
are included under A. evecta , Hoffm. 
3 Thomae, Pringsh. Jahrb. Vol. xvii. 1886, PI. VII, Fig. 3 a. Kuhn also refers to 
these sacs in Todea barbara. Untersuchungen liber die Anatomie der Marattiaceen 
und anderer Gefasskryptogamen, p. 35 : Inaug. Dissert. Marburg, 1889. (Flora, 
1889, p. 457.) 
