56 



J. WATSON, S.J. LYDON & N.A. HARRISON 



Stomata confined to lower side in stomatal strips between nar- 

 rower, non-stomatal longitudinal zones. Within strips stomata in 

 short longitudinal rows or irregularly scattered, sparse or crowded, 

 always longitudinally orientated. Guard cells sunken, next to the slit 

 showing a more or less strongly cutinized ridge ( ' Vorhofleiste' ) and 

 side wall facing lateral subsidiary cell also strongly cutinized. Sub- 

 sidiary cells 4-6. Epidermal cells with slightly sinuous to straight 

 outlines, surface of one or both sides having a median longitudinal 

 ridge. 



Description. In addition to the characters in the original diagno- 

 sis above, Watson & Harrison (1998) have recognised three other 

 distinctive features in four species attributed to the genus 

 Pseiidotorellia Florin. These are: a tendency for ordinary epidermal 

 cells to occur in pairs with the common wall narrower than the other 

 anticlinal walls (Fig. 22L); cutinization of the guard cells as narrow, 

 elongate, thickly cutinized dorsal plates (Fig. 22H, I) and strongly 

 developed polar appendages (Fig. 221, N); unbranched resin canals 

 running along the entire length of the leaf (Fig. 23E, F); all of which 

 are coniferous characters and some at least are probably diagnostic. 

 However, with problems both of generic usage (discussed below) 

 and the original attribution of PseiidotorelUa to the Ginkgoales it 

 seems to us prudent not to embark on emending the diagnosis at this 

 stage. 



Discussion. The genus Pseudotorellia was erected by Florin 

 ( 1 936a: 142) as a form-genus to accommodate species of lanceolate, 

 non-petiolate leaves attributed to the Ginkgoales and subsequently 

 various authors (e.g. Lundblad 1957, Watson 1969, Krassilov 1972, 

 Bose & Manum 1 990) erected a total of ten or more species of multi- 

 veined leaves of this type from Northern Hemisphere Jurassic and 

 Cretaceous floras. Pseudotorellia heterophylla Watson (1969) from 

 the English Wealden was diagnosed on the basis of a very small 

 sample of leaves isolated by Watson (1964) in the first study of 

 fragmentary plant debris from the Hastings Beds. It was immedi- 

 ately obvious both to Watson (1964, 1969) and Harris (pers. comm. 

 1963) that wide, multi-veined elliptical leaves were attributable to 

 the genus Pseudotorellia yet had cuticle which was indistinguish- 

 able from that of needle leaves in the same samples. The demonstration 

 of two veins in the needle leaves strengthened the obvious conclu- 

 sion that the two leaf types represented a single heterophyllous 

 species. This was attributed to the genus Pseudotorellia without 

 hesitation but with a necessary emendment to Florin's diagnosis. At 

 the same time a new genus, Tritaenia Magdefrau & Rudolf (1969), 

 was erected to accommodate the needle leaves of Abietites linkii 

 Romer ( 1 839), long known in great abundance from leaf-coal depos- 

 its in the Wealden of Northwest Germany. However, following 

 World War II, the type material of the German Wealden flora, largely 

 held in collections in East Germany, was inaccessible for many years 

 and serious, practical comparison between English and German 

 species was delayed until 1979 when Fisher (1981) and Watson 

 visited the Museum fiir Naturkunde, East Berlin. Unrestricted access 



to all surviving German specimens followed and, together with the 

 collection of voluminous new English material, led to major new 

 studies, including those of Fisher (1981), Sincock ( 1 985 ) and Harrison 

 (nee Hall 1987). The German Abietites/Pseudotorellia/Tritaenia 

 linkii material proved to have cuticle indistinguishable from that of 

 the English Pseudotorellia heterophylla Watson ( 1 969) and in com- 

 bining these two species Watson & Harrison (1998) decided that the 

 diagnosis of Pseudotorellia Florin, as emended by Bose & Manum 

 ( 1 990: see above), presented the most suitable genus. It became clear 

 that the discoveries made, especially the obvious heterophylly, ren- 

 dered the needle-leaved genus Tritaenia Magdefrau & Rudolf ( 1969) 

 redundant and it therefore became a synonym of Pseudotorellia 

 Florin. This status of the genus Tritaenia has been disputed (Manum 

 et al. 2000) in conjunction with a refusal to accept the identification 

 and synonymy of the English and German material made by Watson 

 & Harrison (1998). 



Pseudotorellia was originally assigned to the Ginkgoales rather 

 than the broad-leaved conifers because of the veins which end freely 

 in the apical margin, but the features described above together with 

 others such as: very thick cuticles; exclusively longitudinal align- 

 ment of stomata; longitudinal arrangement and elongation of ordinary 

 epidermal cells; attribution to Sulcatocladus shoots, are all typically 

 coniferous rather than ginkgoalean features and the two species of 

 Pseudotorellia described here, seem to us more readily accommo- 

 dated amongst the broad-leaved, multi-veined conifers than the 

 Ginkgoales. 



Amongst species in other floras, Pseudotorellia angustifolia 

 Doludenko (see Krassilov 1972: 58) from the Mesozoic of the Bureja 

 Basin, Siberia is known to be attached to a Ginkgo-\ike short shoot 

 (Krassilov 1972: pi. 20, fig. 3) although associated seeds and seed- 

 bearing structures suggest the possibility of coniferous affinity. In the 

 absence of complete knowledge of the female reproductive organs, but 

 with short shoots and the association of Ginkgo-Vikc pollen, Krassilov 

 (1970, 1972) attributed P. angustifolia to a distinct family within the 

 Ginkgoales, suggesting that Pseudotorellia corresponded to a natural 

 genus which could be attributed in its entirety to this isolated family, 

 the Pseudotorelliaceae. However, the attribution of P. linkii to 

 Sulcatocladus shoots points to the coniferous nature of Pseudotorellia 

 from the Wealden of England and Germany. In view of the complete 

 lack of evidence from reproductive structures, we follow the previous 

 suggestion of Watson & Harrison (1998) that Pseiidotorellia Florin 

 should at present be regarded as a gymnosperm form-genus for species 

 attributable to either the Ginkgoales or the Coniferales. 



Pseudotorellia linkii (Romer) Watson & Harrison 



Figs 22-23 



1839 Abies Linkii Romer: 10, pi. 17, figs 2a-c. [Northwest Ger- 

 many] 



1846 Abietites (Abies) Linkii {R6meT}Dunker: I8,pl.9,figs 1 la- 

 d. [Northwest Germany] 



Fig. 22 A-N Pseudotorellia linkii (Romer) Watson & Harrison. A, needle leaves at natural size; left to right V.64174-V.64I95; B, wider leaves from the 

 English Wealden, left to right V. 641 96-V. 64200, x 2.5; C, apical part of an unmacerated leaf showing five veins ending freely, V. 1902 lb (figd Seward, 

 1926; text-fig. 16 A ii). Lower Cretaceous, Western Greenland, x 2.5; D, one of the longest and most complete needle leaves with slightly constricted base 

 and strong midline on upper surface, V,64249, x 2.5; E, middle part of a needle leaf with 4 veins visible, V.64202, x 10; F, part of leaf in Fig. 22C 

 showing 3 of the 5 vascular strands protruding beyond the break, x 10; G, rare leaf apex with extreme pointed tip intact, V. 64553, x 50; H, lower cuticle 

 of mid-region of leaf showing 3 .stomatal bands which merge distally, V.64203, x 30; I, lower cuticle showing prominent stomata and pustules inside the 

 ordinary epidermal cells, V.642()3, x 1 25; J, smooth outer surface of lower cuticle with four stomata visible, V.64289, x 250; K, strongly ridged outer 

 surface of lower cuticle showing three stomata, V.64290, x 250; L, upper cuticle with epidermal cells arranged in files and pustules on the inside of the 

 surface walls. V.64205, x 125: M, inside surface of upper cuticle, showing longitudinal and transverse late division pairs of cells, hypodermis developed 

 on left hand side, V.64289, x 125; N, inside view of stomatal apparatus showing cutinized dorsal plates (radially striate), inner anticlinal walls, part of the 

 ventral walls and polar appendages, V.64289, x 500. 



