66 PRINGSHEIM, ON THE IMPREGNATION 



This opinion, however, as well as Karsten's recent unfor- 

 tunate exposition of the processes said to take place in the 

 " hornlets" and spore-fruit of Vancheria will be found to be 

 untenable from the following description of the act of fruc- 

 tification in that plant. 



But the true process of impregnation in Vaucheria and the 

 development of both kinds of sexual organs — the " hornlet" 

 and the contiguous stunted organ, which is more correctly 

 termed " spore-fruit," \sporangiuv{\ than " spore," takes 

 place in the following manner. Both organs arise like 

 papillary branches from the tube, and in close proximity ; and 

 it is usually the case that the papilla destined to become the 

 " hornlet," is formed sooner than that in which the spore ori- 

 ginates (Plate III. fig. 1). The two fapillce even from the first 

 differ so widely in dimensions, that they can scarcely be con- 

 founded. The papilla which becomes the " hornlet," soon 

 elongates into a short, cylindrical, slender branch, which, at 

 first, rises perpendicularly from the tube, then curves down- 

 wards until it comes in contact with the tube, often forming 

 a second or a third curve, and in this way always represents a 

 more or less stunted branch which frequently exhibits several 

 spiral turns. The papilla of the neighbouring " sporangium," 

 usually begins to appear at the time when the " hornlet" is 

 commencing its first turn ; but the period at which it arises 

 is very indeterminate, for it sometimes appears much earlier 

 whilst the " hornlet" is still perfectly straight, sometimes 

 much later after it has curved, so as to form two limbs of equal 

 length. 



The papilla destined to become the sporangium, gradually 

 enlarges into a considerable sized, lateral out-growth of the 

 tube, far exceeding the hornlet in width, whilst in length it 

 is barely equal to the straight limb of the latter (fig. 2). This 

 out-growth, which is at first symmetrical, ultimately throws out 

 a beak-like prolongation on the side looking towards the horn- 

 let, — the " rostrate appendage," (rostrum) of the sporangium, 

 whence the latter acquires its peculiar form, resembling that 

 of a half-developed vegetable ovule (fig. 3). Up to this period 

 the hornlet as well as the sjjorangium are not shut oif from 

 the tube from which they spring by any septum ; the cavity 

 of the hornlet and that of the sporangium consequently remain 

 uninterruptedly continuous with the parent tube, and are 

 filled with similar contents. A great number of elongated 

 chlorophyll granules lodged in an albuminous plasma — never, in 

 this case, starch — and rounded, larger or smaller oil globules, 

 constitute a dense, internal lining in the tube, the sporangium, 

 and the hornlet. Between this granular, parietal investment 



