Boodle . — Anatomy of the Gleicheniaceae . 743 
Reference to Literature. 
Among the earlier references to Gleicheniaceae is one by 
Von Mohl (’45, p. 115), who mentions that in many thin 
elongated stems, e. g. Gleichenia , the vessels are all united 
into a central bundle. He also points to Platyzoma , previously 
described structurally by Robert Brown (’38-52, p. 2), as 
a connecting link between the above type and that of the 
hollow reticulate cylinder of other Ferns. Presl (’47, p. 2) 
refers to the presence of only a single circular or semicircular 
vascular bundle in the petiole of the Gleicheniaceae, and gives 
diagrams (PL VI) of the petioles of Platyzoma and of seven 
species of Gleichenia , but in each case the bundle is simply 
represented by a circular outline. 
Russow (’72, p. 96) states that the rhizome of G. poly- 
podioides agrees in structure with that of Trichomanes 
radicans. He also describes the petiolar bundle in three 
species of Gleichenia — G. polypodioides , G. dichotoma , and 
G. dicarpa , var. alpina (under syn. G. vidcanica :), and gives 
a fairly accurate diagram (Taf. X, Fig. 10) of the last-named 
variety. The only point of difference from his figure, shown 
by a petiole of this plant examined, was the restriction of the 
phloem inside the xylem-arch to the region of the hooks. 
The sclerotic pericycle is correctly described, and also the 
fibres adjoining the hooks of the xylem. Phloem-fibres are 
also described as being found on the outer side of the xylem 
at the top of the arch in this species and in G. dichotoma. 
They certainly sometimes occur in this position in both these 
species, but are late in differentiation and not always found. 
Russow makes no mention of the internal endodermis in the 
petiolar bundle of G. dichotoma. 
Potonie (’83, p. 39) examined the rhizome of G. Mendelii 
(= G. circinata , var.), and found the typical Gleichenia - 
structure, and notes that the xylem-parenchyma (amylom 
of the hadrom) is a strongly developed tissue. 
Thomae (’86, p. 144) remarks on the fact that in the 
Gleicheniaceae only a single vascular bundle passes into 
