138 Transactions of the [Sess. 



prothallium, bearing both antlieridia and arcbegonia. Tbougb the 

 spores which give rise to this prothallium are alike in size and shape, 

 it does not necessarily follow that they are hermaphrodite. In other 

 words, it is quite possible that there may be some occult difference 

 betwixt them, and that certain spores always produce antheridia or 

 male organs, and others archegonia or female organs, as in the 

 Selaginellas and Ehizocarps with differing spores. This is one of the 

 points in the germination of Lycopods on which we have as yet no 

 certain knowledge. 



The normal stem of the Lycopodiacefe is thickly covered with 

 :small narrow leaves, these being simple, unbranched, and sessile, and 

 possessing only a midrib without lateral veins. The structure of the 

 stem is very characteristic. It is composed of an axial cylinder, 

 surrounded by layers of cellular tissue, the whole being enclosed in 

 looser tissue or parenchyma. From the cellular tissue the long 

 ^adventitious roots found in most species proceed. We will again 

 have occasion to refer to this stem-structure when speaking of the 

 fossil Lepidodendra. 



Lycopods are natives of many parts of the world. Besides our 

 native species already enumerated, numerous forms, many of them 

 very beautiful and some rather curious, are found on the Continent, 

 in the United States, in Canada, the East Indies, Peru, the Fiji 

 Islands, &c. As already said, it has proved to be almost an impossi- 

 bility to grow the exotic forms successfully in greenhouses, and we 

 have to rest content with dried specimens of these for a knowledge 

 of their form and appearance. -*■ 



Passing on to the Selaginellas, we are first called upon to notice 

 our solitary native species, Selaginella selaginoides. This is the 

 Lycopodium selaginoides of Linnaeus, but is generically separated from 

 the Lycopods by the possession of two kinds of spores, large and 

 small — or, as they are usually termed, macrospores and microspores. 

 The plant possesses close afi&nities, nevertheless, with the Lycopods, as 

 evidenced by the name " Selaginella," which is the diminutive form 

 of " Selago," the old term for Lycopodium, and said to be derived 

 from the Gaelic, meaning " beneficial to the eyesight." The Club- 

 mosses, indeed, were at one time frequently used medicinally, but are 

 now banished almost entirely from the British pharmacopoeia, though 

 still in favour on the Continent. It occurs to one, on a little reflec- 

 tion, that Selaginella selaginoides is not a very appropriate name for 

 this plant, now that it has been removed from the class of Lycopods, 

 and that the synonym S. spinosa of Babington and others would be 

 much more descriptive of it. But as it is always as well not to disturb 

 a familiar name without very good cause shown, it may be wiser to 



^ The exotic Lycopods exhibited were from the Herbarium at the E-oyal 

 Botanic Garden, having been kindly lent by Dr Macfarlane. 



