BY W. W. WATTS. 763 



"Pflanzenfamilien," divides all the species into Euhymenophyllum 

 (leaves entire) and Leptocioninm {lasivefi toothed). Leptocio7iium 

 is usually defined as "ultimate segments spinuloso-denticulate." 

 Dr. Christ gives : " Rand des Laubes buchtig gezahnt, Zahne 

 grannenartig zugespitzt." Domin has set up an intermediate 

 subgenus {Hemicyatheon)^ containing plants of both kinds: leaves 

 entire and serrate. His distinctions are : 



Euhymeiiophyllum : ultimate segments entire; indusium con- 

 sisting of two laminae; receptacle as long as the indusium or 

 shorter. 



Hemicyatheon : ultimate segments entire or spinuloso-denticu- 

 late; indusium funnel-shaped below, connate, profoundly bilabiate 

 above (down to half-way or two-thirds) and campanulato-patent; 

 receptacle long-exserted. 



Leptocionium: segments spinuloso-denticulate; indusium divided 

 almost or quite to the base; receptacle enclosed. 



The new subgenus seems, to me, to be open to the objections, 

 that it over-rates the value of the length of the receptacle, a 

 feature often difficult to detect in older specimens, owing to the 

 ease with which the exserted receptacle is broken away; and that 

 it brings together species that, in other respects, differ very 

 widely. On the whole, I prefer the old division into Euhymeno- 

 phyllum and Leptocionium. But the definition of Leptocionium, 

 (segments spinuloso-denticulate) suggests the question whether 

 some species may not be "denticulate" without being "spinuloso- 

 denticulate." A case of this kind has arisen in Domin's H. 

 Shirleyamim. I found specimens of this fern mixed with H. 

 australe (leaves entire) in the Sydney Herbarium (leg. R. F. 

 Waller, 1908; Evelyn Scrub). In size, the fronds did not differ 

 seriously from those of H. australe, with which they were mixed, 

 but they were more transparent and were somewhat arcuate at 

 the apex. I was inclined at first, before I identified this plant 

 with H. Shirleyanum, to regard it as a new variety of II. australe, 

 from which it differs, mainly, in having the ultimate segments 

 minutely denticulate. That the presence or absence of minute 

 denticulations should separate two plants into different subgenera, 

 suggests a serious doubt regarding the current subgeneric classi- 



