276 Bower . — Studies in the Phytogeny of the Filicales. 
(‘ Land Flora ’, Fig. 349, d), but some show relations also with the types 
c and e of Fig. 349. In any case the segmentation is more massive than that 
of the Polypodiaceae. The result is a relatively bulky sporangium, with 
a stalk of several rows of cells (PL XXXIV, Fig. 5). When mature it closely 
resembles that of G. linearis both in shape and in average size. But there 
appears to be a smaller number of spore-mother-cells in each sporangium 
than in this species, and considerably less than in G. fiabellata. Fig. 6 
shows the definitive sporogenous group as seen in a section transverse 
to the axis of the sporangium, and the number of spore-mother-cells is 
fifteen, arranged roughly in four plates. Fig. 7 shows a section of a similar 
sporangium in a median longitudinal section, and the number of the spore- 
mother-cells traversed is twenty. Fig. 8 shows the condition where the 
spore-mother-cells have separated and rounded off. These drawings pro- 
vide an interesting comparison with my drawings for G. flabellata and for 
G. linearis (Figs. 24-26, PI. II of my Studies, V, and Figs. 27-30, 
PI. III). From a comparison of such sections as those shown in Figs. 6 
and 7 the total number of spore-mother-cells in G. pectinata may be 
estimated at some figure probably in excess of 64, which if all were 
matured would lead to an estimated output of spores something in excess 
of 2 56 per sporangium. Actual countings for sporangia of G. pectinata 
gave the result of 422 and 429 for large sporangia, and 228 and 236 for 
small sporangia. The larger are thus seen to approximate to the typical 
number 512, though falling a good deal short of it ; the smaller approximate 
to, but fall short of the typical number 256. 
A comparison of these facts with those for G. linearis and G. flabellata 
indicates clearly a sequence of reduction from the large sporangia of 
G. flabellata , which are few in a sorus, each with an individually large 
spore-output approximating to the typical number 1,024, through G. linea- 
ris , with its smaller sporangia, more numerous in each sorus, and with 
spore-output approximating to or exceeding 256, to G. pectinata with 
sporangia variable in size, but still more numerous in the sorus, and with a 
variable spore-output, approximating in large sporangia to 512, but in 
smaller falling to below 256. The variability in size of the individual 
sporangia makes precise statement precarious. An important point is 
that the variability exists in the species which is in various respects the 
most advanced in the whole genus. 
Turning to the gametophyte of Gleichenia } it presents characters 
of importance as indicating affinity with relatively primitive types. The 
massive form of the prothallus with a marked midrib is characteristic, and 
suggests comparison with Osmnnda. It bears in some species ‘ marginal 
1 Rauwenhofif : La Generation sexu^e des Gleicheniacees. Arch. Neerland., 1890. Campbell : 
Mosses and Ferns, 2nd Ed., p. 336; also The Prothallium of Kaulfussia and Gleichenia. Ann. 
Jard. Bot. Buit., 2 e s6r., vol. ix, p. 80. 
