332 Howe : Observations on the 



Mme. Weber-van Bosse, we have been able to see four of the six 

 individual plants, by which, she writes, the evident type of the 

 species is represented in the Kutzing herbarium. 



Graf zu Solms-Laubach, though admitting the close relation- 

 ship of Acetabulum crenulatum and A. Caraibicum, attempts the 

 following distinctions in his key * to the species of the genus : 



" Disci infundibuliformes saepius plures superpositi, radiis 

 apiculo convexo." 



A. crenulatum 



" Discus planus, radiis apice emarginatis, apiculum parvum 



erentibus." 



A. Caraibicum. 



The alleged difference in the form of the disc appears not to be 

 borne out either by Kutzing' s original figures or by the specimens 

 preserved in his herbarium. In all the latter, so far as we have 

 seen them, with one exception, the disc is as strikingly infundibuli- 

 form as in any condition of A. crenulatum ; and this one exception, 

 if it may be so called, is a disc which has been artificially flattened 

 on a piece of mica and evidently decalcified. Moreover, the discs 

 are sometimes superposed in pairs in A. Caraibicum, as shown in 

 the original figures and in the specimens themselves. The plants 

 with two discs were made by Kutzing to constitute his variety 

 calyculata, but they were apparently growing with the others and 

 do not deserve a varietal name any more than the similar condi- 

 tions which have long: been recognized in A. crenulatum. In re- 



*> --v.x* xv^vv^ 



gard to the apiculum, there is little difference. In Kutzing's plants 

 it is very conspicuous when the sporangium is young, but becomes 

 more or less obscure with age — as also is generally acknowledged 

 to be sometimes the case in A. crenulatum. The apiculum is, 

 however, discernible in each of the four Kutzingian plants exam- 

 ined. The paucity of the original material forbade any extended 

 observations on the form of the apex of the mature sporangium in 

 the soaked-out condition, but we found none so strongly emargi- 

 nate as figured by Kutzing. The apices of the matured sporangia 

 appear rather to be merely truncate or slightly retuse, more as 

 figured by Count Solms (/. c, pi. i. f. io) } and we think it must be 

 admitted that a subtruncate sporangium-apex is quite normal in A. 

 crenulatum. Solms-Laubach mentions also the "slightly calcified 

 cap" as one of the characters by which Acetabulum Caraibicum 



*t. c. 20. 



