RHIZOi 



total want of spiral vessels. Thnt, however, waa a mi 



nol exist among them. Brown saj - that he hi I them 



in which he originally failed to perceive them, and in several • I 



Martius also found them in Langsdorffia, in the form of ' 



rhizome, stem and branches, and Mohl in similar | 



small quantity compared to the mass of the plant , wn add 



cular Bystem of all these parasites is uniform and more Bimple than I 

 ui the t'.n greater part of Phaenogamous plants; that the spiral, ■ 

 modifications of it, is the only form of vessel hitherto observed in 

 them; and that the large tubes or vessels with fri lenl 

 corresponding imperfect diaphragms, and variously marked surface, which 

 have received several names, as vasa porosa, punctata, vasiform cell 

 tissue, dotted ducts, & ■■.. and which are bo conspicuous in the majority 

 arborescent Phaenogamous plant-, have never been observed in any part 

 Btrictly belonging to these parasites. (Linn. I. ml. xix. 231.) He, 



however, does not attach systematical importance to this curiou 



The flowi in general formed upon some symmetrical plan, the pro 



portions varying from genus to genus. But in a singular d< aua 



called Sarcophyte the flowers are not reducible to symmetry, as fa 

 yet be 11 observed. It has not, however, been examined in a philosophical 

 manner. 



The Beeds of many Rhizogens have escaped the observation ol who 



have had the beat opportunities of examining them. Even I I the 



common Cytinus Ilypocistis of the South of Europe are unknown. But if 

 there lias been a want of facts concerning this part of the structure t ; 

 has been speculation in abundance for which the reader is referred to the 

 last edition of this work. I can positively confirm th< the 



elder Richard i Mem. Mus. viii. t. xxi.), who gives to Cynomorium coccineum 

 an embryo. I find in that plant that the Beed consists of a muci 

 mass filled with angular particle-, which are doubtless loosely coheril 

 They contain Btarch in a very minutely globular state, 'tit are 

 composed of gum. On one Bide of this seed is a globular embi 

 like a .speck, but found, when properly examined, to be a glol 

 cells, destitute of Btarch, enclosed within the albumen, and apparently un- 

 divided on any part of its Burface. It is, however, difficult to 

 positively upon this point, on account of its Bmallness, and 1 am i I 

 that it isnot very slightly 2-lobed. Francis Bauer too ascertain* ! -: 



Rafflesia Arnoldi to have the ordinary structure, a Btrong ind 

 the Beeds would not be so anomalous as has been rep I, and 1 



an undivided embryo in the Beed of the Bame plant, | /. nn. Rra •■■ t. 



kxv.), a circumstance continued by the observations of Brown. F< 

 Bauer found in Bydnora Africans what Beems i<< 1"' a . ■ 

 I / "/. t. sxx.) of the same nature, and the research - of W 

 Hooker leave no further room for doubting that all Rl 

 embryonate. 



Sueh being the supposed facts that have I lined with n 



these singular parasites, it only remains to notict 

 tained regarding them by systematic botanists. Dr. R 

 aided by the microscopical drawings of the two Ba 

 advantages for considering the question, appi 

 of regarding Rhizogens as a distinct class. H 

 being unquestionably allied to Birth worths, and then 

 His objections to regarding Rhizogi • a distinct da* 



i 



