Hollo WAT. — Studies in the New Zealand Species of Lycopodiuin. 287 



Summary. 



The conclusions arrived at by Lang (14), Bower (4), and others 

 with regard to the significance of the mode of dependence of the 

 Lycopodium young plant upon its parent prothallus niay here be 

 briefly stated. Lang, following Treub, would regard not only the 

 L. cernuum type of prothallus, but also the L. ^ernuum, type of 

 young plant, as being primitive for the genus. He says (14, 

 p. 302), " The form of the young plant of L. cernuum, &c., is 

 not to be regarded as recent and adaptive, but as possessing an 

 important phjdogenetic bearing." With regard to the epiphytic species 

 and L. Selago, he suggests that the protocorm stage has there been lost 

 owing to the subterranean habit, and quotes I'reub's statement of the 

 existence of a rudimentary jDrotocorm in L. Phlegmaria. In the sub- 

 terranean types also of L. clavatum and L. complanatum the protocorm 

 has been lost, and the large development of the foot is to be regarded 

 as an adaptation in accordance with the lai'ge size of the prothallus 

 and the lengthy dependence of the young plant upon it. Bower looks 

 upon the L. Selago type of embryogeny, where the only extraordinary 

 feature is the varying length of the hypocotyl, as being the most simple 

 and primitive within the genus Lycopodium. In the types of L. clava- 

 tum and L. complanatum he would see an adaptation from the L. Selago 

 type in accordance with the subterranean saprophytic specialization of the' 

 prothallus. He inclines to deny (3, footnote on p. 248) that the swelling 

 in the embryo of L. Phlegiiuiria stated by Treub to be a rudimentary 

 protocorm is to be interpreted as such. The protocorm of the L' cernuu/in 

 cycle of affinity he would regard merely as a specialization, classing it 

 rather as a parenchymatous swelling such as is the foot, and doubting 

 any general application of the protocorm theory in the Avhole genus. The 

 protophylls are, in accordance with his view, to be judged simply as 

 turgid outgrowths from the protocorm. Goebel. in- the first edition of 

 his "Organography" (10, pp. 231-33), does not favour Treub's theory 

 of the protocorm, and lays emphasis on the fact that protocorms are 

 found in certain epiphytic orchids. One other writer's views must also 

 be briefly stated in order to bring forward the main lines of discussion 

 along which the consideration of the Lycopodium. embryogeny is being 

 directed. Lady Isabel Browne (5, p. 223) has suggested that the proto- 

 corm is to be regarded as a modified form of stem due to reduction. 

 She lays emphasis, on the one hand, on the great development of the 

 stem in the oldest fossil Lycopods known to us, and, on the other hand, 

 she conclude? that " since vascular tissue penetrates for some distance in 

 the protocorm of Jj. laterale, this organ cannot, at least in that species, 

 be dismissed as a mere parenchymatous sAvelling." 



No new facts of great importance emei'ge from the study of the 

 morphology of the young plants of L. Billardieri, or of L. voluhile, 

 L. scariosnm, L. densum. and L. fastigiatum. The foot of the young 

 plant of L. Billardieri seems to be larger tha,n that figured by Treub for 

 L. Phlegmaria. In the young embryo plant of L. fastigiatum there is 

 only one leaf-rudiment encircling the apex of the stem, and not a pair 

 as figured by Bruchmann for X. clavatum and L. annotinum. In 

 L. voluhile, and to a less extent in Z. scariosum and L. fastigiatum, a 

 slight strand of vascular tissue is given off from the main stele into the 

 foot. 



But the study of the protocorm in L. laterale and L. ramulosum brings 

 to light facts of considerable interest. First of all, it must be emphasized 

 that, as in the other species in which a protocorm has been found, it is 



