Notes. 
158 
Our object in publishing the present note (pending the preparation 
of a detailed paper on the anatomy of Lindsay a, which, owing to the 
difficulty of obtaining alcohol-material of other species, must occupy 
several months) is to call attention to the prima facie inferences to be 
drawn from the occurrence of this type of stele in the adult stems 
of these Ferns. The occasion is the more opportune owing to the 
publication in the last number of this journal of Mr. Boodle’s paper 
on the anatomy of the Gleicheniaceae, in which he gives a detailed 
account of structures already partially described by Poirault (Ann. Sci. 
Nat., Bot., 1893), structures having an important bearing on the phylo- 
genetic question which we propose to outline. 
The 1 Lindsaya- type’ of stele, at present known in the creeping 
rhizomes of the five species 1 (or four species and one variety) of 
Lindsaya enumerated above, and also in that of Davallia repens , is a 
monostele showing in cross-section a central mass of xylem, consisting 
of scalariform tracheids intermingled with parenchyma, and surrounded 
by a complete ring of phloem, pericycle and endodermis, as in 
Gleichenia or Lygodium , but differing most strikingly from these 
Ferns by possessing, in addition to the external phloem-mantle , a strand 
of phloem completely embedded in the xylem near the dorsal surface of 
the latter. This strand of internal phloem consists of typical sieve- 
tubes mixed with parenchyma and separated by one layer of similar 
parenchyma from the surrounding xylem (Fig. 9). 
As the node is approached from below 2 , the strand of internal 
phloem forms a dorsal projection on the side corresponding to the 
leaf-insertion, thrusting up the dorsal * vault’ of xylem, as Trdcul calls 
it, on that side (Fig. 10). An accumulation of parenchyma arises in 
the phloem-strand immediately ventral to this bay, and in the midst of 
this accumulation endodermal cells appear which soon come to enclose 
a few parenchymatous cells (Fig. 10). The dorsal bay of phloem 
rapidly extends laterally outwards, and at the same time the internal 
endodermis with its enclosed parenchyma moves up dorsally behind it, 
so that the phloem of the bay assumes the form of a slightly curved 
plate lining the inside of the thrust-out xylem arc on one side of the 
dorsal vault. The vault now breaks at the point near its centre where 
1 The addition of the three species mentioned in the first footnote on p. 157 raises 
the number to eight. 
2 The following description is taken from Lindsaya orbiculata , but the other 
species agree in essentials. 
