194 KIDSTOX: THE FLORA OF THE CARBONIFEROUS PERIOD. 
Linopteris Presl. (Dictyopteris Gutbier not Lamouroux) though 
rare in Britain, must not be omitted. In the form of the frond 
and pinnules it is similar to Xeuropteris, and specimens not 
showing the nervation might easily be overlooked as belonging 
to that genus, but it is at once distinguished by the nervation, 
the veinlets of which unite among themselves to form a net-like reti- 
culation (Plate XXX., fig. 2. Linopteris ohliqua Bunbury sp. x 3J). 
Though this genus is certainly not common in Britain, it 
may be more common than supposed through being passed over 
for Neuropteris. 
PECOPTERIDE.E. 
This family holds an important place among palaeozoic ferns. 
Pecopteris Brongt. is the chief genus and contains many large 
and fine species. It is chiefly represented in the Upper Coal 
Measures, and Fecopteris arhorescens may be regarded as the 
type (Plate XXVIL, fig. 3). 
The pinnules in Pecopteris are attached to the rachis by 
the whole of their base. They have straight sides and rounded 
apices. The pinnules are sometimes united among themselves 
at the base and possess a strong central mid-rib, from which — 
according to the species— are given off simple or dichotomously 
divided veins which extend to the margin. 
The fructification of many of these ferns consists of four 
or five exannulate sporangia arranged in a stellate group, from 
which circumstance the genus Asterotheca has been proposed for 
them, though not generally adopted (Plate XXYIL. fig. 4). 
In the Middle Coal Measures, Pecopteris [Asterotheca) is 
represented by few species, but Pecopteris [Aster'otheca) Miltoni 
is fairly plentiful. Though this species also occurs in the Upper 
Coal Measures, it is there associated with man}^ other Pecopterids 
w^hich are not found below that horizon. 
The fronds of Pecopteris were of very large size and most 
probably some of the tree fern stems were the trunks of Pecopteris. 
The Pec. plumosa Artis sp. ( = Pec. dentata Brongt. Plate 
XXVIL, fig. 1, Plate XXXI., figs. 1-4), so common in the 
Middle and Upper Coal Measures, forms the type of the genus 
