18 THE FERNS AND 



Only one plant belonging to the order has hitherto been found in 

 the colony. 



Order IV. — Salvinieae. This is another order of aquatic plants, 

 which is represented in New Zealand by a very common and 

 extremely pretty little plant of the genus Azolla. In many parts of 

 the colony it covers the water of lagoons and ditches with a green or 

 reddish mantle, thus resembling the common duckweed. It floats on 

 the surface of the water, and sends down numerous roots, which do 

 not, however, attach themselves to the soil at the bottom. As in 

 the last order (with which some botanists unite this), the reproductive 

 organs are inserted near the base of the fronds. They are, however, 

 different in structure, being only 1-celled, and containing one kind of 

 sporangia arranged along a central column which stands up in the 

 middle of the sporocarp. Thus one sporocarp contains macro- 

 sporangia only, in each of which is one macrospore. Other sporo- 

 carps contain only microsporangia, each containing a number of 

 microspores. The prothallus is developed from the former. 



Order V. — Lycopodiacese (Club Mosses). These are distinguished 

 from ferns and other allied plants by many characteristic features. 

 They are all terrestrial, are furnished with diohotomously branching 

 roots (except Psilotum, which has no true roots, and Phylloglossumi, 

 in which they are tuberous), and develop their branches very 

 irregularly. The leaves are always small and 1-nerved, and in very 

 many species are decurrent on the stems. The reproductive organs 

 are contained in capsules or sporangia, which are usually solitary in 

 the axils of particular leaves, but sometimes these fertile leaves are 

 so crowded or imbricated together as to form the fructification into 

 spikes. These sporangia are 1-celled {Lycopodium), 2-celled (Tmesip- 

 ieris), or 3-celled (Psilotvm), but contain only one kind of spores. 



The process of development from the spore has been imperfectly 

 observed in one species of Lycopodium only, and with this exception 

 it may be said that there is no information on the subject as far as 

 our New Zealand genera are concerned. Probably most botanists 

 have at one time or another tried to become famous by studying the 

 development of this order, but no one has succeeded up to the 

 present in throwing light on the matter, so that there is still a 

 magnificent field of research open in this direction to any enterprising 

 .student. 



