308 Pteridophyten. 



Chrysler, M. A., The Nature of the Fertile Spike in the 

 Ophioglossaceat. (Ann. Bot. p. 1 — 18. 1910.) 

 In Botrychiwn virginianum the petiolar vascular Strand arises 

 as a curved bündle; higher up it becomes horseshoe-shaped and 

 divides into two, internal phloem appearing in the adaxial conca- 

 vity; a little higher a small concentric Strand breaks off from each 

 of the free edges of the horseshoe and higher up again joins the 

 internal face of the Strand from which it was cut off, but in a rather 

 more adaxial positicn, so that when the two adaxial ends of the 

 trace break off, converge and enter the spike the small detached 

 Strands are fused with and form the incurved adaxial ends of the 

 main Strands; these may remain separate or fuse again, but when 

 they give off vascular Strands to tbe sterile pinnae exactfy the 

 same process as that outlined above is repeated, save that the 

 departing Strands diverge instead of converging. In Botrychium 

 tematum the curved leaf trace may be nearly closed adaxially; in 

 some plants the main Strand before the departure of the vascular 

 supply of the spike, gives rise at each end to a small or marginal 

 Strand, wich higher up again joins on to the said main Strand; but 

 unhke what occurs in B. virginianum part of the marginal Strand 

 may pass out into the spike, the vascular Strand of which is accor- 

 dingly C shaped; in other cases the marginal Strand may be repre- 

 sented by its Upper end only, appearing as a slight projection from 

 the adaxial part of the main Strand; in other cases it pursues a 

 down ward course for a little distance, swerving towards the main 

 Strand, but dies out before reaching it. B. lanceolatum and B. 

 ramosum (B. matricariaefolium) resemble B. tematum in having a ■ 

 nearly closed petiolar Strand; the bundles supplying both fertile and 

 sterile segments break off from the adaxial edges; they mayapproxi- 

 mate but do not fuse. The writer confirms Roeper's account of the 

 leaf trace of B. lunaria. Here the trace divides while still in the 

 stem — the Strands supplying the leaf lobe and the spike arise 

 from the free adaxial edges and at this point there is a slight pro- 

 minence on the inner side of the trace recalling in position the 

 Upper end of the marginal Strand. In B. simplex the vascular struc- 

 ture of the petiole is that of a reduced B. lunaria. The leaf trace 

 of B. obliquum is U-shaped; in an abnormal form with three Spikes 

 the vascular supply of the lowest, normally situated spike. arose 

 from the fusion of two Strands from the adaxial edges of the U; 

 the vascular supply of the two higher ones originated as two singie 

 bundles from points near, but not at the edge of the trace. In 

 Helminthostachys the petiole has an internal Strand, derived from 

 one of the adaxial ends of the tract (Campbell figures two, the 

 origin of the second being unknown). The vascular supply consists 

 ot two bundles, from the right and left edges respectively of the 

 curved series of bundles and of two more, representing the internal 

 bündle, which after its fusion with the main petiolar bündle emerges 

 as a pair of Strands. A jounger specimen contained fewer bundles 

 in the trace; a small Strand was given off from one of the adaxial 

 Strands and again anastomoses with the main Strands — these having 

 meanwhile united edge to edge and finally emerged to supply the 

 spike. According to Prantl the leaf trace of Ophioglossum lusita- 

 nicum early divides into three; the two lateral bundles each give 

 off a Strand and these, fusing, enter the spike. In 0. vulgatum the 

 writer confirms Holle's account of the behaviour of the Strands; 

 both those passing into the fertile and those passing into the sterile 



