Kusano, Further studies on Aeginetia indica. 287 



proper host-root. In this plant the embryo is so much reduced in 

 form as to appear like a younger stage of a dicotyledonous embryo 

 (Koch, 1878, p. 259), being merely an oval cell-mass, and the 

 changes that take place diiring germination show certain pecu- 

 liarities. At first the radicular half of the embryo develops into 

 a filamentous root (Koch, 1883, p. 189), while the plunralar half 

 remains throughout in the endosperm, acting as an absorbing organ. 

 Differing from Lathraea-seeälmg the parasitism of this seedling is 

 effected by the root-tip, provided it abuts on a host-root lying be- 

 force its course. In his culture-experiments Koch (1883) assumed 

 that in germination the seeds required a chemical Stimulus from 

 the host-root. Such being all that we know, at present, about the 

 early stage of development of the Orobanchaceae, it appears to 

 me to be not the less interesting to extend our study on Aeginetia 

 which exhibits a close resemblance to the last mentioned species 

 of Orobanchaceae, on account of the structure of the seeds as well 

 as the vegetative organs, and to ascertain how far what was found 

 on the latter plant is applicable to the former. 



While the present study was carried out with this end in 

 view, I have never undervalued the problem about the condition 

 which the seeds of such holoparasite require in germination. Al- 

 though it has been ascertained by the above mentioned authors 

 that the Stimulus of the host-root is invariably neccessary to ger- 

 mination in plants of this family, the nature of the Stimulus has 

 not yet been studied with accuracy. Concerning this point I can 

 not yet express any definite view, but as it seems to me that the 

 results of a few incidental experiments are suggestive for a further 

 study on this subject, I will note them briefly in the present paper. 



Methods. 



The seed of Aeginetia being very fine and pulverous, a special 

 treatment is required in observing its germination. In order to 

 observe easily the successive stages of germination, and of the 

 development of the seedlings, I transplanted, a month or two pre- 

 viously, some vigorous host-plants in pots of 15 — 20 cm in diameter. 

 These being kept sufficiently moist, the plants began to produce 

 after a while young rootlets mainly traversing between the wall 

 of the pots and the soil inside. When a thick mesh-work was 

 thus formed by the rootlets I lifted up carefully the plants from 

 the pots, laid the seeds of Aeginetia upon the meshes, and then 

 put the plants again in the pots as betöre. By taking the plants 

 from time to time out of the pots without disturbing the arrange- 

 ment of their root-system on which the seeds were laid, I was 

 able to follow in detail the changes that took place during the 

 germination and subsequently. 



The seeds used in the experiment were collected in the pre- 

 ceding year and kept dry. Under favourable conditions they ger- 

 minated within two weeks in the early summer. However I could 

 observe no germination to take place in seeds preserved in a 



