The following passage, which forms a fitting introduction to an account of two other genera of ancient ferns, is taken from a description of an ascent of Mount Ophir in the Malay Peninsula by Dr A. R. Wallace in his well-known book on the Malay Archipelago:--'After passing a little tangled jungle and swampy thickets, we emerged into a fine lofty forest.... We ascended steadily up a moderate slope for several miles, having a deep ravine on the left. We then had a level plateau or shoulder to cross, after which the ascent was steeper and the forest denser till we came out upon the Padang-Batu, or stone-field.... We found it to be a steep slope of even rock, extending along the mountain side farther than we could see. Parts of it were quite bare, but where it was cracked and fissured there grew a most luxuriant vegetation, among which the pitcher plants were the most remarkable.... A few coniferae of the genus Dacrydium here first appeared, and in the thickets, just above the rocky surface, we walked through groves of those splendid ferns, _Dipteris Horsfieldii_ and _Matonia pectinata_, which bear large spreading fronds on slender stems, 6 or 8 feet high'(49). [Illustration: Fig. 11. _Matonia pectinata._ A group of plants in a wood on Gunong Tundok, Mount Ophir. (Photograph by Mr A. G. Tansley.)] The two genera Matonia and Dipteris afford exceptionally striking examples of survivals from the past. Matonia is represented by two species, _Matonia pectinata_ (Fig. 11), which grows abundantly on the upper slopes of Padang-Batu in dense thickets on the rock faces where, as Mr Tansley states, its associates are a species of Gleichenia, Dipteris, and a little _Pteridium aquilinum_ (Bracken Fern). _Matonia pectinata_ occurs also on Bornean mountains at an altitude of over 3000 ft. and descends to the coast on some of the Malay islands. The other species of the genus, _Matonia sarmentosa_, has so far been found in one locality only, Niak, Sarawak, where it was discovered by Mr Charles Hose. _Matonia pectinata_ has a creeping stem covered with a thick felt of brown hairs bearing tall fan-shaped fronds divided into numerous comb-like branches thickly set with narrow linear leaflets on which circular clusters of spore-capsules are sparsely scattered. In some respects Matonia is unlike other ferns; the fronds constitute a striking feature, and the anatomy of the stem is still more distinctive. In the form, development, and arrangement of the sporangia (spore-capsules)--organs which from the constancy of their characters have long been recognised as the most useful basis for classification--Matonia exhibits distinctive features.