94 
Notes on Recent Literature. 
Finally the outer part of the ground-tissue of this curious fossil 
was traversed by numerous roots, running parallel with the stem. 
It would, of course, be rash to draw any final conclusions as 
to the affinities of Tietea from the material at present available. 
The fossil consists of a short fragment of the stem, incomplete 
transversely ; the leaves, after they become free from the stem, and 
the fructifications are completely unknown. In the absence of the 
latter organs it is impossible to be sure whether we are dealing with 
a true Fern or a Pteridosperm. Nevertheless the vascular structure 
of the plant is highly peculiar and after reading Count Solms’ 
detailed analysis of it it is impossible not to be struck by points 
suggesting comparison with certain better known groups. 
The most obvious comparison is with the Psaronieae, and it is on 
this comparison that Count Solms dwells, though he concludes by 
stating that for the present “we must resign ourselves to leaving 
the question of the relationship of Tietea to the Psaronieae in 
suspenso ” (l.c., p. 700). 
Taking first the points of resemblance, one of the most curious 
is the similarity of the root-traversed peripheral tissues of Tietia 
and those of the Psaronieae. The paucity of the material limited the 
number of sections of those parts that could be obtained ; but while 
admitting that more light might be thrown on this matter Count 
Solms remarks that the structure of this tissue seems to point to 
the conclusion that it had a similar origin to that of the root- 
traversed-tissue of the Psaronieae. His own recently published 
investigations on the so-called radiciferous cortex of Psaronius seem 
to show that this tissue is mainly cauline in origin, but that a 
certain amount of the peripheral part arose from the roots them¬ 
selves. 1 It would surely be a significant fact if this morphologically 
peculiar tissue should obtain also in Tietea. Count Solms further 
points out that the structure of the xylem is not essentially different in 
Tietea and Psaronius, though in latter the parenchymatous intrusions 
found in Tietea “become unusually unimportant (‘ausserordentlich 
zurticktreten ’) in Psaronius and are practically confined to the 
occurrence of small nests of parenchyma in the tracheal tissue.” 
But there are also very striking differences. One of the most 
obvious of these is that in Tietea the trace originates as a 
number of distinct bundles, while in Psaronius it is a single wide 
band. Further the presence of the sheath that ends in lobe¬ 
like prolongations is peculiar to Tietea. Neither of these 
differences, however, appears of such importance as the following 
facts: (1) Psaronius is definitely polycyclic, while Tietea, though 
highly polystelic, shows no sign of polycycly; (2) the reparatory 
strands, which in Psaronius take part in the formation of the trace 
and give rise to the adventitious roots, are absent in Tietea, 
where the latter function is assumed by the bundles of the lobe-like 
prolongations, the absence of reparatory strands seems to be corre¬ 
lated with the absence of polycycly; (3) the leaf-trace of 'Tietea is 
not only multi-fascicular at its origin, but the numerous bundles 
composing it soon arrange themselves in more than one series, even 
excluding those destined to the sheath; (4) the plate- or band-like 
steles of Tietea appear very different from the solenostelic, usually 
annular steles, of Tietea. 
1 Solms-Laubach, H. Graf zu. “ Der tiefschvvarze Psaronius Haidingeri 
von Manebach in Thuringen.” Zeitschrift fiir Botanik, Bd. 3, Heft. 11, 1911. 
