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Transactions. 



and brownish at the centre. Sections showed that this was due to a some- 

 what compact core of narrow cells containing much protoplasm (fig. 4). 

 Minute starch-grains were present in abundance in the basal portion of 

 the plantlets, especially in the epidermal cells and central cells. These 

 stained blue with an aqueous solution of iodine. No fungal hyphae were 

 seen. The leaves were crowded with stomata. 



IV. Root-tubercles. 



Treub (1887) has described root-tubercles in L. cernuum thus : " The 

 root-tips change into propagative organs of a remarkable form. These 

 root gemmae or bulbs produce on germinating young plants very much 

 like those which come forth from prothalli.'" This method of vegetative 

 reproduction is found in several species of Ophioglossum. Land (1911) 

 thoroughly investigated colonies of 0. vulgatum in a Mexican locality, in 

 which many young plants were seen to be present. He noticed that the 

 plants were generally in groups of three to ten, usually radiating from a large 

 plant. When the root-system of these groups was. laid bare it was found 

 that nearly all the plants of a group were connected, and that the smaller 

 plants were produced by adventitious budding of the roots of the larger 



Fig. 4. — Lycopodium cernuum. Transverse section of basal region of such a plantlet 



as that shown in fig. 2. X 100. 

 Fig. 5. — Lycopodium ramulosum. Root-tubercle with attached and detached plantlets. 

 X 6. 



plants. Pfeiffer (1916) found the prothalli of 0. vulgatum in a wet locality 

 near Chicago. At the end of her paper she remarks that probably repro- 

 duction of this species by vegetative spread is by far the more common 

 method, but scattered among plants so produced are the far less numerous 

 specimens arising after gametophyte production has occurred. 



I have found root-tubercles in both L. cernuum and L. ramulosum. In 

 the former of these species instances were observed in which the actual 

 tip of the root had turned into a swollen tuber, as described by Treub. 

 Again, in the case of the adventitious plantlets of the same species described 

 in Section III of this paper, two instances were seen in which a tuberous 

 swelling occurred immediately behind the apex of the root of a plantlet — 

 i.e., the root-tip itself was not concerned with the process but grew on in 

 the ordinary way. I was not able to collect sufficient material to enable 

 me to trace the development of the root-tubercle of this species into the 



