t 



M. Pringsheim on the Pro-Embryos of the Charse. 323 



To distinguish them from others, I will call these shoots 

 "naked-footed twigs." The manifold phenomena called forth 

 by the various degrees of development of the bark on the lower 

 joints of these naked-footed twigs I pass over here entirely; but, 

 on the contrary, I indicate particularly that even these shoots, in 

 their development, and especially in the formation of their mor- 

 phological members from the vegetative cell always present at 

 their apex, follow the general law of development of the shoots 

 of Chara. 



The second kind of twig-like structures, which occur with 

 the naked-footed twigs on the older nodes which have passed 

 through the winter, must strike the observer, even from their 

 external appearance, by the far greater deviation of their lower 

 parts from the normal structure of the shoots of Chara. It is 

 to these structures, under the name of ^' progerms of the twigs" 

 (Zweigvorkeime) , that I wish here in the first place to call 

 attention. 



Whilst every twig issuing from a node commences with a 

 distinct joint, appearing green from the well-known chlorophyll- 

 rows of the CharcBf which bears immediately above it the first 

 normal node furnished with leaves, the progerms of the twigs 

 commence with a perfectly colourless shorter or longer joint, in 

 which the chlorophyll-rows are always wanting. This is followed 

 by an extremely imperfectly developed and always leafless node, 

 the place of which is even frequently occupied by a single cell, 

 elongated into the form of a joint. Upon this, again, there fol- 

 lows a more or less elongated but always naked joint, which, in 

 its appearance already presents a greater resemblance to the 

 stem-joints of the CharcB, and this joint apparently bears the 

 first circle of leaves. 



But this also is remarkable for a disproportionate development 

 of the parts, which is never seen on any other whorl of leaves : 

 amongst the leaves apparently belonging to it one is constantly 

 distinguished by its excessive growth, far exceeding any inequa- 

 lities amongst the leaves of a whorl, that may occur now and 

 then in normal whorls. 



It is only from hence that the twig becomes perfectly normal, 

 that is to say, the following joints, nodes, and leaves are exactly 

 like the first joints, nodes, and leaves of a normal naked-footed 

 or barked lateral twig ; so that it evidently appears as if the true 

 twig originates as a lateral shoot in the axil of the above-men- 

 tioned excessively developed leaf of the first whorl. 



And this view is in fact fully confirmed by the developmental 

 history, which at the same time furnishes an unexpected expla- 

 nation of the nature of the excessively developed pseudo-leaf. 

 Thus it shows that this does not belong as a leaf to the first 



22* 



