P. punctatum Thunb. is, as noted under Hypolepis tenuifolia, so near to that species as to be very difficult of distinction, especially when dry. The technical differences between the two species are the recurved lobule forming a pseudo-involucre in H. tenuifolia, absent in P. punctatum, and the position of the sori—on the margins of the sinuses in Hypolepis, and farther from the margins in Polypodium. But in practice these are not altogether trustworthy. In some forms of Hypolepis the spurious involucre is hardly or not at all developed, and sometimes it appears slightly in Polypodium, while the sori of the latter are frequently distinctly marginal. When green, however, the viscid-pubescence of the stipes, rachides, and even of the pinnules of P. punctatum at once identifies this species. P. pennigerum Forst. attains its greatest luxuriance in shaded gullies on the banks of streams, where it develops a caudex 1–4 ft. or more in length, giving the plant the appearance of a small tree-fern. P. australe Mett. is not uncommon. It occurs on rocks and rather dry banks in the forest, but it is more common on the trunks of forest-trees. Var. villosum Hook. appears to be more plentiful than the type. It is difficult to get a good specimen, as the fronds are often attacked by some grub or insect. P. grammitidis R. Br. is abundant on the trunks of small and the upper branches of large trees. Occasionally it is found among moss-covered peaty soil where the original forest is giving place to scrub. P. tenellum Forst. is undoubtedly one of our loveliest ferns, climbing as it does to a considerable height up the trunks of trees, usually in damp lowland woods, and forming a graceful drape to the dull-brown trunks. In the mature state this fern is simply pinnate, the pinnae “entire or obscurely undulate-crenate” (Manual, p. 1011); but the juvenile state is quite different—the pinnae are distinctly bipinnate, usually with 3 pairs of stipitate pinnules, and a prolonged lobulate termination. P. serpens Forst. occurs plentifully, climbing by its long branched rhizome up trees or rocks. Its thick leathery fronds, dimorphous in form, render it a curious rather than an attractive plant. P. dictyopteris Mett., better known under its old name, P. Cunninghamii Hook., is found in most forests in the damper parts, on trunks of trees or on rocks. It usually grows in considerable masses. It is remarkable how retentive of life this fern is. In summer the plants, especially those on rocks, look dry and withered, but a good shower of rain soon fills them up, and they look almost as fresh as ever. P. pustulatum Forst. occurs plentifully in woods and forests, clothing the trunks of trees to a good height. It is one of the most variable, if not the most variable, of our ferns. In the juvenile form the frond is simple, linear-lanceolate, and in one variety this form is persistent, producing sori, but never attaining the size of the more common form with pinnatifid fronds. P. Billardieri R. Br. is very plentiful on trees and rocks. This species, too, is exceedingly variable in form and size, according to the conditions of its habitat. Its juvenile form also is simple, and in dry situations this form is persistent. In a damper habitat the frond is deeply pinnatifid, with sometimes as many as 12 segments on each side. 25. Gleichenia Smith. Of the five species of Gleichenia occurring in New Zealand all but G. dichotoma Hook., or, as it is now called, G. linearis C. B. Clarke, are more or less common.