Campbell. — Studies on some J avanese Anthocerotaceae. If. 99 
it is doubtful whether this is ever the case, as Leitgeb supposed it to be. 
Except in microtome sections it would be quite impossible to recognize 
the slender columella obscured by the massive sporogenous tissue which 
surrounds it. The sporogonium becomes pear-shaped (Fig. 43), and the 
single layer of sporogenous tissue increases very much in thickness, 
becoming ultimately three or four cells thick (Fig. 44). Above the summit 
of the columella, which is not always very clearly defined in the upper 
region, the sporogenous tissue divides rapidly and forms a large mass 
(Fig. 43). The differentiation of the sporogenous and sterile cells of the 
archesporium is entirely similar to that of N. orbicidaris. There is a 
pretty regular alternation of horizontal layers of fertile and sterile cells, 
the latter (. sp ) very soon becoming recognizable on account of their 
larger size. 
The foot in Notothylas is much smaller than in Dendroceros and 
Text-fig. 2. Median sections near the base of older sporophytes of Notothylas ( A 
Megaceros (B), and Anthoceros (C), showing the relative size of the archesporium in the three 
genera. 
Anthoceros , corresponding to the smaller size of the sporophyte. The 
root-like outgrowths are, however, well developed and appear at an early 
stage in the growth of the embryo (see Figs. 38, 39). 
It is clear that in normal cases, at least, the sporogonium of 
N. javanicus develops in precisely the same way as that of N. orbicularis 
or the other Anthocerotaceae. There is no evidence of a secondary 
formation of the columella from potentially sporogenous tissue, as Leitgeb 
surmises is the case in some forms of N. fertilis. The great reduction 
of the columella in some of the stunted sporogonia makes it quite 
conceivable that this may be carried a stage further and that sporogonia 
might be formed without a columella ; but no cases of this were seen, 
although a good many young sporogonia were sectioned, and there is 
no question that usually, at least, a columella is formed and that it 
always originates in the same way as that of the other Anthocerotaceae. 
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