_Selaginella lepidophylla_, a tropical American type, popularly known as the Resurrection plant, and often erroneously spoken of as the Rose of Jericho[87], possesses the power of rolling up its shoots during periods of drought and furnishes an example of a species adapted to conditions in marked contrast to those which are most favourable to the majority of species. The only British species is _Selaginella spinosa_ named by Linnaeus _Lycopodium selaginoides_ and occasionally referred to as _Selaginella spinulosa_ A. Br. (not to be confounded with a Javan species _S. spinulosa_ Spring[88]). • • • • • =Isoetaceae.= _Isoetes_ (fig. 132), of which Mr Baker in his _Handbook of the Fern-Allies_ enumerates 49 species, is a type apart, differing in habit as in certain other characters from the other members of the Lycopodiales. Some botanists[89] prefer to include the genus among the Filicales, but the balance of evidence, including resemblances between _Isoetes_ and extinct Lycopodiaceous plants, would seem to favour its retention as an aberrant genus of the group Lycopodiales. Some species are permanently submerged, others occur in situations intermittently covered with water, and a few grow in damp soil. _Isoetes lacustris_ is found in mountain tarns and lakes of Britain and elsewhere in Central and Northern Europe and North America. _Isoetes hystrix_[90], a land-form occurs in Guernsey, North-East France, Spain and Asia Minor. Lycopodiaceae. The monotypic genus _Phylloglossum_, represented by _P. Drummondii_ of Australia and New Zealand, though interesting from the point of view of its probable claim to be considered the most primitive type of existing Lycopodiaceous plants, need not be dealt with in detail. A complete individual, which does not exceed 4 or 5 cm. in length, consists of a very small tubercle or protocorm bearing a rosette of slender subulate leaves and prolonged distally as a simple naked axis which overtops the foliage leaves and terminates in a compact cluster of small scale-like sporophylls, each subtending a single sporangium[91]. _Lycopodium._ It would be out of place in a volume devoted mainly to fossil plants to attempt a comprehensive account of the general morphology of recent species, and indeed our knowledge of the anatomical characters of the genus is still somewhat meagre. For purposes of comparison with extinct types, it is essential that some of the more important morphological features of existing species should be briefly considered. The additions made to our knowledge of the gameophyte[92] of European and tropical species during the last two decades have revealed a striking diversity in habit.