202 



curved towards the centre of the sorus; they are 3 — 5-celled, 6/^ broad at the base, 

 upwards a Httle thinner. The sporangia are born of a stalk cell as in the other 

 species; they are 26 — 32 « long, 21 — 24 n broad. After the evacuation, a new spor- 

 angial cell is cut off from the stalk cell within the empty sporangial wall. 



I agree with Heydrich and Collins in retaining the species in the genus 

 Rhododermis. When occurring in its disc-shaped form it resembles R. elegans so 

 much that it differs only in the dimensions of the cells of the frond, and there 

 but slightly. 



The species grows on the leaves of Zostera produced in the foregoing year, 

 but also in shed leaves. It has been met with in the months of April to August, 

 in all these months in disc-shaped and inflated specimens and with sori. In April 

 the sporangia were yet undivided; in May and June unripe and ripe sporangia were 

 met with, in July and August ripe sporangia were found, but also emjitied and 

 regenerated ones. The species has also elsewhere been found with sporangia in 

 spring and summer. 



Localities. Lf : Repeatedly at Nykobing (!, C. H. Ostenfeld). — Ku: In several places at Hirs- 

 liolmciie (!, Ostenfeld, Henn. Petersen); Frederiksliavn, Bussercv, and between Borrebjergs Rev and Marens 

 Rev; ZL, S.E. of Noidre Ronner, (;,r) m and 11 m. — Sa: Off Risskov at Aarbus. 



Fam. 8. Hildenbrandiacese. 



The family of the Hildenbrandiacese, established long since (Comp. Raben- 

 HORST, Fl. eur. Alg. Ill, 18(38, p. 408) and still maintained by Schmitz in 1882 (Hauck, 

 Meeresalgen., p. 37), was later abandoned by this author as the presumed cystocarpia 

 of the genus Hildenbrandia had proved to be conceptacles of tetrasporangia, and he 

 therefore ranged this genus under (jenera incevke sedis in 1889 (Flora, p. 22). In 1897 

 ScMMiTz and Hauptfleisch range it as a dubious Condlinacea. On the other hand 

 De Toni places it under the Squamariacew in a subfam. Hildenbrandtiecc (Sylloge 

 Alg. Vol. IV, sect. IV 1905, p. 1713). I think it better to consider the genus as a repi-e- 

 sentative of a particular family intermediary between the Sqiiamariacece and the 

 Corallin(ice(c. Although the sexual reproduction is unknown, the family is sufficiently 

 characterized by the want of incrustation with lime of the frond, by the presence 

 of immersed conceptacles of sporangia, and by the oblique divisions of the spor- 

 angia. The conceptacles resemble those of the Corallinacece but develop in another 

 wa}^, as will be mentioned below. Oblique divisions of the sporangia do not occur 

 in the CoralUnaceiv, but are characteristic of several Squamariacece. 



Hildenbrandia Nardo. 

 1. Hildenbrandia prototypus Nardo. 



Nardo, De novo genere Algarum cui nomen est Hildbrandtia prototypus. Oken's Isis 1843, p. 675; Hauck, 

 Meeresalg. p. 38. 



Zonaria deusta Lyngbye, Hydr., 1819, p. 19 ex parte; cfr. notula. 



