VAUCHERIA. 



[ 672 ] 



VEGETABLE KINGDOM. 



sometimes met with having several living re- 

 gions of this kind, shooting out into branches, 

 separated from each other by dead, empty 

 lengths of the filament. 



Besides the vegetative reproduction above 

 described, the Vaucherice are reproduced by 

 spores formed by the concurrence of two 

 distinct kinds of reproductive organs. Fila- 

 ments growing on damp ground ordinarily 

 exhibit lateral organs of two kinds, associated 

 together, but variously grouped and collected 

 in varying numbers at particular points, ap- 

 parently according to external conditions. 

 The larger kind of organ appears first as a 

 pouch-like process, which expands into a 

 squat flask-shaped body, stalked or sessile, 

 the neck of which is gradually turned over 

 in the development, until it projects at one 

 side, the form then somewhat resembling 

 that of a bird's head (or a chemist's glass 

 retort cut off short at the neck). Near this 

 on the main filament, or on a common pedi- 

 cel with one or more of the bird's-head or- 

 gans, is developed another organ, at first 

 straight and tubular, but soon curving over 

 into the form of a hook or scroll, without, 

 however, expanding. The expanded part of 

 the bird's-head organ (or sporangium) be- 

 comes filled with dense green granular mat- 

 ter, and cut off by a septum from the main 

 filament. The upper part of the " hook" is 

 likewise cut off by a septum, and the con- 

 tents of the apical cell thus formed are of 

 light colour, and soon lose most of the chlo- 

 rophyll. From the association of these two 

 kinds of organ, and the production of spores 

 in the sporanges, it was supposed, as long 

 ago as in Vaucher's time, that they repre- 

 sented sexual organs. Vaucher thought the 

 " hooks" discharged a kind of pollen to fertilize 

 the sporanges. Other algologists, especially 

 Nageli, supposed or asserted that a conjuga- 

 tion took place between them (like that in Spi- 

 rogyra), a view more or less favourably re- 

 ceived until a few years since, when Karsten 

 asserted that he had actually observed it in all 

 its details. But Pringsheim has lately pub- 

 lished a very complete and certainly more 

 trustworthy account of the development of 

 these structures, in which he denies the con- 

 jugation, but asserts that the " hook " is an 

 antheridium, and that when mature it bursts 

 at the apex and discharges biciliated sper- 

 matozoids resembling those of Fucus, which 

 enter the simultaneously opened neck of the 

 sporange and fertilize its granular contents. 

 The contents become isolated from the wall, 

 secrete a proper coat, and form a free cell 



(spore) lying in the sporange, its granule 

 matter gradually losing the green colou 

 and becoming brown. Two coats, at leasi 

 are developed, and the spore ultimate!; 

 escapes by the decay of the parent filamen 

 and sporange. According to Pringsheim 

 about three months elapse before germina 

 tion, in which process the outer spore-coa 

 splits, and the inner grows out into a tube 

 forming the basis of a new ramification o 

 the Fawc^ena-filament. 



In the systematic works on Algology, nu 

 merous species of aquatic and land Vaucherit 

 are described ; but we agree with Thuret ii 

 believing that the characters by which mos 

 of the forms are distinguished are unessential 

 therefore we omit any synopsis of them 

 Even V. racemosa, Decaisne, appears merel; 

 an extreme of the kind of developmen 

 producing V. geminata. Thuret propose 

 the name V. Ungeri, to include all but V. ra 

 cemosa ; Hassall suppresses the name V. da 

 vat a, as indicating a form common to all tin 

 species, of which he describes a large num 

 ber. We do not find anything sufficiently 

 distinctive in the characters of the marim 

 species cited by Harvey. 



The admirable essay of Unger should bi 

 consulted by those studying the gonidia 

 reproduction. 



BIBL. Vaucher, Conferees d'eau douc* 

 (Ectosperma) ; Hassall, Brit. Fr. Alg. 

 Harvey, Brit. Mar. Alg. p. 195 ; Unger 

 Nova Act a, xiii. p. 11, Die Pflanze im Mom 

 der Thierwerdung, Vienna, 1843; Decaisne 

 Ann. des Sc. nut. 2 ser. xvii. p. 430; Thuret 

 ibid. xix. p. 266 ; Karsten, Bot. Zeitung, x 

 p. 85 (1852) ; Pringsheim, Ber. Berlin Akad 

 March 1855 ; Ann. Nat. Hist. 2nd ser. xv 

 p. 346 ; Alex. Braun, Verjungung (Hay Soc 

 Vol. 1853, passim}, Alg. unicell. (1855) 

 p. 8, 105; Nageli, Neuer Algensyst. p. 175 

 pi. 4 ; Itzigsohn, Bot. Zeit. xi. p. 225 (1853) 



VEGETABLE IVORY. This substanci 

 consists of the seeds of the Palm calle( 

 Pliytelepnas macrocarpa, composed of j 

 large round mass of bony ALBUMEN, in whicl 

 a small embryo is imbedded. Slices of thi: 

 ivory-like albumen, placed under the micro 

 scope, afford very beautiful examples of ve 

 getable cells with the cavities almost oblite 

 rated by SECONDARY DEPOSITS (PI. 38 

 fig. 23). 



VEGETABLE KINGDOM. The larg< 

 number of natural orders of Angiospermou! 

 Flowering Plants and the subordinate cha 

 racter of their diversities in microscopic 

 structure, lead us to depart from the plan or 



