10 J. E. Areschoug, 



fructification of the species of Lessonia occurs, as in Macroajstis, upon the surface 

 of the fronds and there forms large patches. In the present species the sori are 

 situated beyond the middle of the leaf, they are oblong and nearly as broad as the 

 lamina, of which they carry away the upper part when decaying, causing theirs 

 broad apices to be two-horned. In none of ours specimens is the point perfect, 

 all the spores we have seen being situated on the edges of the sorus, which has it- 

 self fallen away from the frond». — Folia, de quibus hie qujeritur, duplicis sunt generis, 

 nempe 1) folia proxime prseteriti anni, quaj jam dejecta erant cum fructificatione, 

 quam produxerant, et 2) folia sequentis anni, bicornia, quae ilia in apicibus pro 

 more portaverant usque in maturitatem et occasum. Defoliationem et foliationem 

 in utraque specie eodem niodo fiere, omnibus facile patere credimus. 



3. LESSONIA LAMINARIiEOIDES Post. & Rupr. 



Radix distincte ramosa, rami ramiilosi, ramuli haiistoriis donati. 

 Truncus inferne teres, subsimplex, usque 2,5 cm. longus et 3 — 4 mm. crassus, 

 mox superne quater et quiuquies dicliotomus, ad dichotomias ultimas 

 semilineam circiter latus, cortice fusco vestitus, sed lacunis annulisque 

 carens. Medulla in sectione basali oblonga et utrinque acutiuscula. Fo- 

 lia (sicca) chartacea, margine integerrima, fuscescentia, lineari-oblonga, 

 usque 60 cm. longa et 7 — 10 cm. lata, majora minorave et apice 

 plerumque fragmentum folii preeteriti anni portantia. Sporangia et para- 

 nemata in media lamina et in utroque latere maculas elongatas, colons 

 obscurioris formantia. 



Syn. Lessonia laminariceoides Post, et llupr. Illustr. Alg. pag. 9 tab. XXXVII, fig. e 

 (sec. J. Ag'. Spec. 1 p. 152), Kütz. Spec. p. 582, Rupr. A\gx Ocliotfiises 

 (Lessonia laminariceformis) § 29 p. 157. 



Crescit frequenter in mari Ochotensi, ut testatur larga inde a museo 

 Petropolitano accepta collectio. 



Hsec species formse tenuiori Laminan're saccliarince tarn est similis, ut utraque 

 facile confundi possit, sed truncus quater vel quinquies dichotomus foliaque geminata, 

 fissura adscendente orta, magnam ofiferunt diiferentiam. Est itaque vera Lessonia! 

 Sporangia et paranemata hujus speciei sunt illis Laminariacearum in genere simil- 

 lima, sed in Laminariaceis, quae e longinquo adportantur et aqua dulci lavata; sunt, 

 horum orgauorum formam non facile est rite deterniinare. 



Lessonia nigrescens, L. Suhrii earumque formse habent omnes, quantum nos 

 quidem experti sumus, callum radicalem magnum et (in sicco) durissimum; Les- 

 sonia fuscescens vero et L. laminariceoides radices distinctas. Ilia? habent folia 

 crassa, subcoriacea; hte folia subchartacea. Lessonia ovata Hook., L. fiiscescenti 

 sine dubitatione proxima, nobis videtur incerta species. 



