185 



The Works of Schimper and Braun^ contain a careful des- 

 cription of the facts which they observed in the transition of spiral 

 to whorled phyllotaxis as seen in the adult condition : an explanation 

 of the phenomena, however, was not tried. 



Ail whorls are described by them in terms of spiral construction; 

 the case of alternating whorls of four members is considered to 

 be a /4 phyllotaxis. Between the last member of a lower whorl 

 (the cyclur) and the first member of a higher whorl (the cyclarch) 

 the divergence is altered by the prosenthesis. Most authois on 

 phyllotaxis hâve made the observation that the introduction of 

 this notion of prosenthesis gave no explanation of the phenomena 

 and that nothing was gained by it. Undoubtedly this is quite true, 

 but when we carefuUy read the authors* descriptions, we come 

 across some valuable éléments. In the first place we admire their 

 thorough observation, the detailed statement of facts. They were 

 the first to see that whorls do not always alternate" but can also be 

 put together in a more complex way, of which many instances are 

 described. But perhaps their most valuable contribution is the 

 distinction they make^ between ,,untere Wirtel", low whorls, oc- 

 curring in the végétative régions of the plant, and „obere Wirtel", 

 high whorls, in the inflorescences and in the flowers. According to 

 the authors, the différence between them is, that pentamerous 

 whorls in the végétative régions are formed from a V5 phyllotaxis, 

 whereas the higher pentamerous whorls are "j^ spiral constructions. 



It is quite probable that the conception of the low whorls as being 

 derived from. a V5 spiral phyllotaxis will prove to be wrong; but that 



■' K Fr. Schimper, Beschreibung des Symphytum Zeyheri und seiner zwei 

 deutschen Vervvandten der S. bulbosum Schimper und S. tuberosum Jacc}., Geigers 

 Magazin fur Pharmacie Bd. 28, 1829, relmpressed in Heidelberg 1835 wlthout the 

 authors knowlng; Al. Braun, Vergleichende Untersuchungen ùber die Ordnung 

 der Schuppen an den Tannenzapfen etc., Nova Acta phys. med Ac. C. L. C. n. c. 1 5, 

 1831, p. 196 ; Al. Braun Dr. Cari Schimper's Vortrage iiber die Moglichkeit eines 

 wissenschaftlichen Verstândnisses der Blattstellung etc., Flora, 18, 1, 1835, p. 145, 

 161. 177. 



" Symphytum, 1. c. p. 82, Tannenzapfen, 1. c. p. 360, S. 99. 

 ^ Tannenzapfen, p. 355, Vortrage, 1. c. p. 164. 



4 



