66 Sykes . — The Anatomy and Morphology of Tmesipteris. 
of preservation, and all these bore at their apex numerous fertile branches 
in all stages of development (Text-fig. II, p. 64). Such plants do not 
appear to have been among Bertrand’s or Dangeard’s material, but are 
figured by Jennings. 1 
Each ‘ sporophyll ’ consists of a short axis at the apex of which two 
leaves and a synangium are situated. The synangium is borne on a short 
pedicel or sporangiophore, which may, however, in unusual cases become 
much elongated, and even attain a considerable length. 2 The leaves are 
exactly similar to those on the main axis. The synangia are generally 
bisporangiate, consisting of two lobes, each dehiscing longitudinally, and 
separated from each other by a plate of sterile tissue. A few abnormal 
fertile branches are described below. 
III. Short Summary of Previous Work on Tmesipteris. 
The most exhaustive account of Tmesipteris is found in Bertrand’s 
monograph 3 , which deals very fully with both the anatomy and the 
morphology. Dangeard 4 has given a more concise description of the 
genus, of which he recognizes several species, differing chiefly in the shape 
of their leaves and synangia. This author was the first to investigate the 
rhizome, and he studied to some extent the fungus 5 found in its cells, and 
considered by him to be a member of the Chytridiaceae. Jennings and 
Hall 0 have described the anatomy of Tmesipteris , but few new facts are to 
be gleaned from their account. 
The results of the above authors may be shortly summarized as 
follows: Tmesipteris is a rootless plant, the underground portion absorbing 
moisture by means of rhizoids, containing a fungus and having a single 
concentric stele, which has usually two exarch protoxylem groups. In no 
case has an endodermis been seen either in the rhizome or in the aerial 
stem, and the minute structure of the phloem is as yet uninvestigated. 
The aerial portion of the plant bears leaves and sterile and fertile branches. 
The branches each bear a pair of leaves, and in the case of the fertile 
branches each has also a two-lobed spore-producing organ, formed on the 
end of a short pedicel arising at the point of divergence of the two leaves. 
The aerial stem also is monostelic, but here the phloem forms a continuous 
ring, while the xylem is arranged in several mesarch groups. Bertrand 
states that the leaves and branches each receive a single trace with a single 
protoxylem group, but Dangeard describes the formation of diarch steles 
to supply the branches. Each leaf-trace arises from one of the xylem 
groups of the stem by division at or near the place of origin, but each 
1 Jennings and Hall, 1891, PI. I, Fig. II. 2 Thomas, 1902, p. 343. 
3 Bertrand, Recherches sur les Temsipt^ridees. 
4 Dangeard, Le Botaniste, ii, pp. 163-219, PI. IX-XV. 
5 Dangeard, Le Botaniste, ii, p. 222-30. 6 Jennings and Hall, 1891. 
