ON TIIE GEEMINATION OF CHARA. 309 



bulblets are reservoirs of reserve substances. From the cells clustered 

 on their apex, or at the point of their insertion, pro- embryos may be 

 given off ; indeed, we may particularly call attention to the fact that 

 they were observed more especially on those of undoubted root origin. 

 Accessory pro-embryos are often produced abundantly, not only on 

 specimens growing on the ground, but also on the bulblets or 

 tubercles, and on portions of root isolated in water. The starchy 

 contents of the bulblets' disappear in proportion to the formation of pro- 

 embryos. The matted turf-like growth of the perennial C. aspera may 

 doubtless be ascribed in a great measure to the plentiful production of 

 pro- embryos from the root, and the stems issuing from them. Moreover, 

 I found that the formation of pro-embryos on the joints of older roots 

 of Tohjpella glomerata was not uncommon, and I once saw them on 

 the end of an old detached root of Nitella liijalina. 



Finally, as Wahlstedt and liordstedt have already shown, the ap- 

 pearance of accessory pro-embryos on the first node, and at the base 

 of the primary root, of germinating plants is extremely frequent. 

 To complete the sketch of the essential germinating plant, we may 

 be permitted to return once more to the consideration of its adventi- 

 tious branches. 



Hitherto only adventitious branches have been discovered on the 

 stem-node of the pro- embryo ; no accessory pro- embryos. Both kinds 

 of shoot occur on the root- node and base of the primary root. True, 

 I found branches only on older plants, in which the pro-embryo was 

 fully lengthened out and become green, and the stem- shoot pretty far 

 developed, of Chara foetida and fragilis, and Nitella hyalina, and 

 these plants whose culture had been somewhat neglected, were grow- 

 ing in vessels of water without any soil. Accessory branches appear 

 in both places — usually only one in each place — more frequently, 

 according to my estimation, on the root-node than on the root-basis. 

 Many, but not nearly all, of the cultivated examples bore them ; and 

 on the same cultivated species, and not seldom on the same indivi- 

 duals, there were accessory pro-embryos, oftener, according to calcula- 

 tion, proceeding from the base of the primary root than from the root- 

 node of the primary pro- embryo. It was, however, not alone on 

 neglected plants, but also on carefully cultivated examples, rooting in 

 soil, that accessory pro- embryos were frequent in both positions, and in 

 many species of quite regular appearance. Besides the species 

 already named, I found them in most others of which I had anything 

 approaching ample specimens— thus in C. crinata, Tolypella intricata 

 and glomerata, and Nitella capitata, and indeed in all these species in 

 both positions. It is not unusual for one of the tube-like, outgrowing 

 peripheral cells of the base of the primary root (never the tip of the 

 primary root itself) to assume in an early stage the structure of an 

 accessory pro- embryo, which is very little behind the primary pro- 

 embryo in development. In Chara crinita and Tohjpella intricata 

 this was frequently observed ; and once also in Nitella capitata. But it 

 happens much oftener that the accessory pro-embryos do not appear 

 until a later stage of growth of the principal pro-embryo and its 

 stem-shoot, and therefore they are found much more abundantly in 

 young plants, in which the point of the pro-embryo is full grown. 

 Several accessory pro-embryos may issue from either of the two places 



