A STUDY OF SYMPHYOGYNA ASPERA 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 196 



. Florence A. McCormick 



(with plates xxx-xxxii) 



The species of Symphyogyna are tropical and semitropical liver- 

 worts. They grow best in abundant moisture, and especially well 

 in dripping water, but do not thrive in standing water. As a 

 genus distinct from the other genera of Hepaticae, it was first 

 described by Nees ab Esenbeck and Montagne (9) in 1836, and 

 four species were described: S. brasiliensis, S. Hockstettii, S. dif- 

 formis, and S. circinata. Up to this time the first three species 

 had been included in Jungermanni. The fourth species was evi- 

 dently a new one. Additional forms were discovered, and later 

 Gottsche, Lindenberg, and Nees ab Esenbeck (18) listed 24 

 species. Schiffner (31), in his census of 1909, reports 27 species. 



Symphyogyna is closely related to P allavicinia , which is well 

 known in our flora. These two genera have an interesting parallel 

 series of plant bodies, ranging from the entire ribbon-like form to 

 the deeply dissected and leaflike thallus which closely resembles a 

 fern. While many of the species of Symphyogyna are distinctly 

 anacrogynous in form, others with their leaflike lobes are strikingly 

 like the acrogynous Jungermanniales, so that the genus as a whole 

 holds a high rank among the Jungermanniales. Moreover, in the 

 development of the sporophyte and the late differentiation of its 

 sporogenous tissue, it almost approaches the condition of the mosses. 

 Stephani (33) considers Treubia insignis, with its acrogynous char- 

 acters, more closely related to Symphyogyna than to any other 

 genus, and Schiffner (31) places Monoclea, whose position among 

 Jungermanniales has been severely contested by others, especially 

 Johnson (22), close to Symphyogyna. These two relationships, 

 whether real or imaginary, give some indication of the range of 

 habit of the genus. 



Comparatively little is known of the morphology of Symphy- 

 ogyna. Leitgeb (26) gives a general survey of the genus and 



401] 



[Botanical Gazette, vol. 58 



