148 



L. HrLLIS-COLINVAUX 



Fig. 45. H. lacrimosa. Specimen from Florida, Content Key, 23 IV 66, Croley 1061. 

 (Photograph by The Ohio State University Department of Photography.) 



This delicate species is readily distinguished from all other species 

 of the genus by its small size and by the presence of spherical or 

 pyriform (tear-shaped) segments. It shares with one of the commonest 

 growth forms of gracilis, apparently the most closely related species, 

 several features including a lax decumbent habit and an essentially 

 dichotomous inner cortex. The general appearance and degree of 

 attachment of the peripheral utricles are also common to the two 

 species. 



Microscopically, lacrimosa is characterized by capitate secondary 

 utricles which appear circular in cross-section and support up to 18 

 peripheral utricles. The pattern of nodal medullary filaments is complex, 

 and is perhaps best interpreted as a combination of short and complete 

 fusion with, for example, two filaments sometimes resulting from a 

 fusion of three or four. The usual type of complete fusion also occurs. 



The restricted distribution of this species may be partly accounted 

 for by the ease with which such small specimens are overlooked. 



