364 



SCIENCE 



[N. S., Vol. XL., No. 1028 



director of the botanic gardens of Buiten- 

 zorg was rendered famous by his personal 

 investigations, and chiefly by his classical 

 researches on the Lycopods. These were 

 followed up by other workers, and notably 

 by Bruchmann; so that we now possess a 

 reasonable basis for comparison of the dif- 

 ferent types of the family as regards the 

 prothallus and embryology, as well as of 

 the sporophyte plant ; and all of these char- 

 acters must be brought together as a basis 

 for a sound conclusion as to their phyletic 

 seriation. The most peculiar living Lyco- 

 pods are certainly Isoetes and Phylloglos- 

 sum, both of which are found in Australia. 

 The former need not be specially discussed 

 here, as it is a practically world-wide genus. 

 It must suffice to say that it is probably the 

 nearest living thing to the fossils Lepido- 

 dendron and Sigillaria, and may be de- 

 scribed as consisting of an abbreviated 

 and partially differentiated Lepidostroius 

 seated upon a contracted stigmarian base. 



But Phylloglossurn, which is peculiar to 

 the Australasian region, naturally claims 

 special attention. The plant is well known 

 to botanists as regards its external features, 

 its annual storage tuber, its leafy shoot with 

 protophylls and roots, and its simple shaft 

 bearing the short strobilus of characteristic 

 Lycopod type. But its prothallus has never 

 been properly delineated, though it was 

 verbaUy described by Dr. A. P. W. Thomas 

 in 1901.^ Perhaps the completed statement 

 may have been reserved as a pleasant sur- 

 prise for this meeting. But the description 

 of thirteen years ago clearly shows its simi- 

 larity to the type of Lycopodium cernuum. 

 The sporophyte compares rather with L. 

 inundatum. Both of these are species 

 which, though probably not the most prim- 

 itive of the genus, are far from being the 

 most advanced. As all botanists know, the 

 question of the position of Phylloglossurn 



2 Frot). Boy. Soo., Vol. 69, p. 285. 



chiefly turns upon the view we take of the 

 annual tuber and its protophylls. Treub, 

 finding similar conditions in certain em- 

 bryos of Lycopods, called it a " protocorm, ' ' 

 and believed that he recognized in it an or- 

 gan of archaic nature, which had played an 

 important part in the early establishment 

 of the sporophyte in the soil, physiologically 

 independent of the prothallus. I must not 

 trouble you here with the whole argument 

 in regard to this view. Facts which pro- 

 foundly affect the conclusion are those 

 showing the inconstancy of occurrence of 

 the organ. Mr. HoUoway has recently de- 

 scribed it as of unusual size in your native 

 L. laterale, as it is also in L. cernuum. But 

 it is virtually absent in those species which 

 have a large intraprothallial foot, such as 

 L. clavatuni, as well as in the genus Sela- 

 giiiella and in Isoetes. In L. Selago, which 

 on other grounds appears to be primitive, 

 there is no "protocorm." Such facts ap- 

 pear to me to indicate caution. They sug- 

 gest that the ' ' protocorm " is an opportunist 

 local swelling of inconstant occurrence, 

 which, though biologically important in 

 some cases, is not really primitive. 



If this is the comparative conclusion, 

 then our view will be that Phylloglossurn is 

 a type of Lycopod which has assumed, per- 

 haps relatively recently, a very practical 

 mode of annual growth. Related, as it ap- 

 pears to be on other points, with the L. 

 inundatum group of species, it has bettered 

 their mode of life. L. inundatum, dies ofE 

 each year to the very tip of its shoot, so that 

 only the bud remains to the following sea- 

 son. It is notable that Goebel has described 

 long ago how the young adventitious buds 

 of this species start with small "proto- 

 corms," quite like those of Phylloglossurn 

 itself, or like the embryo of L. cernuum. 

 And so we may conclude that in Phyllo- 

 glossum a tuberous development, contain- 

 ing a store to start the plant in the spring. 



