4 2 5 
some Species of Gleichenia. 
number of fibres in the nodal island, or in its continuation in the petiole, 
varies considerably in different varieties ; thus Boodle (’01, p. 725) found 
only three in G . circinnata, while for the var. Speluncae , Poirault (’ 93 , p. 181) 
figures a petiole with thirteen fibres, and in var. semivestitawe found sixteen. 
In G. rupestris only a single fibre was present in one case. 
The internal pericycle of the leaf-trace and petiolar bundle may become 
sclerenchymatous, 1 this tissue being then composed of septate fibres with 
thick walls and numerous pits. 2 Examples of this were found in G. circin- 
nata, and may be compared with the case of G. alpina . R.Br. (-G. dicarpa 
Fig. 2. Gleichenia circinnata. Protoxylem-element (6 in Fig. 1). 1. Lowest section of the 
element showing sub-scalariform markings. 2. Another section of the same, nearer the stem-apex. 
3. Still higher section, showing two elements. x 540. 
var. alpina , H.B.), in which both inner and outer pericycle in the petiolar 
bundle become sclerotic (Boodle, ’01, p. 716). The xylem-parenchyma in 
the stele may also become lignified and fibrous ; but this was only observed 
in the variety semivestita , while specimens of typical G. circinnata did not 
show this character. Poirault, however (’ 93 , p. 173), describes the presence 
of ‘ quelques rares cellules sclereuses ’ among the scalariform tracheae in 
G . alpina. R.Br. ( G . hecistophylla , Cunn.). In G. circinnata and many other 
species of Gleichenia , including G . pectinata^ phloem-fibres are occasionally 
to be found in the petiolar bundle. 
1 The pericycle of the nodal island may also become sclerenchymatous, e. g. in G. circinnata 
var. semivestita. 
2 These septate fibres may be well shown by staining with Hofmann’s blue, the preparations 
being made in the following way : Sections are soaked in eau de Javelle for about five minutes, 
then washed in spirit, and treated with a solution of Hofmann’s blue (Griibler’s) in weak glycerine 
(50 per cent.). The tracheae and all other lignified elements stain deep blue. Permanent pre- 
parations may be made by mounting the sections in glycerine-jelly coloured with Hofmann’s blue. 
The brown fibres of the cortex and nodal island remain brown (unless bleached by long soaking in 
eau de Javelle) ; they are thus easily distinguished from fibres belonging to the pericycle of the leaf- 
trace or nodal island, since all these elements readily take up the blue stain. In the same prepara- 
tions the dots on the radial walls of the endodermal cells were also well stained. Comparison with 
sections stained in phloroglucin showed that the action of Hofmann’s blue, when used as described 
above, was limited to the walls which could also be stained by phloroglucin. Maule’s reaction 
(with permanganate of potash, hydrochloric acid, ammonia) showed staining of the same walls, 
excluding perhaps the Caspary’s dots. 
G g 2 
