Fig. B shows at _a_ a section of a leaf-axis in the act of branching and the row of branchlets at _b_ represents a further stage in subdivision. At _sp_ in fig. A the section has cut through a single sporangium characterised by a group of larger (“annulus”) cells on one side of the wall. [Illustration: FIG. 306. A–D. _Botryopteris ramosa_; stem and frond axes. (A × 7; B × 15; C × 26; D × 13. From sections in the Cambridge Botany School Collection.) _px_, protoxylem; _sp_, sporangium; _e_, epidermis.] This slender fern with its numerous repeatedly branched leaves may perhaps have lived epiphytically on more robust plants. _Botryopteris antiqua_, Kidst. Fig. 307. This species, recently described by Kidston[1130] from the Culm of Pettycur near Burntisland, is represented by sections of a small stem with a cylindrical stele 0·40 mm. in diameter composed entirely of scalariform tracheae without any recognisable protoxylem. The petioles are larger than the stem; the meristele (fig. 307) is oval with protoxylem elements on the slightly more rounded adaxial face. As Kidston suggests, this stem may belong to a scrambling plant which required support to bear its relatively large leaves. An interesting feature is the absence of projecting teeth in the leaf-trace, a character in marked contrast to the ω form assumed by the petioles of _Botryopteris forensis_ (fig. 319, G) and _B. hirsuta_. This leads Kidston to suggest that the vascular strand of the petiole tends “to become more simple ... as traced back in geological time.” The greater similarity in this species between the stele of the stem and that of the petiole is probably another mark of a more primitive type. [Illustration: FIG. 307. _Botryopteris antiqua_: Petiolar vascular strand. (After Kidston: × 65.)] • • • • • In these three types, _Grammatopteris_, _Tubicaulis_, and _Botryopteris_, we have monostelic plants, for the most part of very small size, with leaf-traces varying in shape from the oblong band-form in _Grammatopteris_, and the oval form of _Botryopteris antiqua_, to the ω type represented in its most pronounced form by _B. forensis_. In several species the stem stele is endarch. Our knowledge of the leaves is very meagre: in _B. forensis_ they were repeatedly branched and apparently bore small fleshy pinnules; the sporangia, though differing from those of recent ferns, may be compared with the spore-capsules of Osmundaceae as regards the structure of the annulus. The abundance of hairs on the stems and leaves of some species, the tracheal sheath in the sporangium described by Oliver[1131] as _Tracheotheca_ (= _Botryopteris?_), and the apparent absence of a large well-developed lamina, may perhaps be regarded as evidence of xerophilous conditions. II. Zygoptereae.