Alga.] SOCIETY ISLANDS. 77 



secundis ovatis acuminatis apice obscure serratis enerviis laxe reticularis membranaceis nitidis, 

 seta liEvi apice arcuato-curvata, theca (parva) ovata brevi, operculo hemispliEerico mucronato. 

 (Tab. XIX.) 



This plant is loosely tufted, and the mass exhibits a brownish hue, like many Jungermannia. Although 

 the leaves be slightly secund, it belongs certainly to the distichous division. 

 Tab. XIX. Hypnum fuscescens. Fig. 1, Plants:— natural size ; Jig. 2, Single plant:— magnified; fig. 3, 



Portion of the stem, with leaves; fig. 4, Single leaf; fig. 5, Capsule; fig. 6, Lid; fig. 7, Calyptra; fig. 



8, Portion of the inner peristome; fig. 9. Portion of the outer do.: — all more or less magnified. 



Ord. LIV. HEPATICiE. Juss. 

 1. Anthoceros IcEvis. Linn. 

 1. Jungermannia multifida. Linn. 



Ord. LV. LICHENES. Jim*. 



1. Lecidea Cocoes. Sw. Lich. Am. p. 2. t. 2. 



1. Parmelia pannosa. Ach. — Sw. Lich. Am. p. 6. t. 6. 



The Parmelia strigosa and Sandwichiana of Gaudichaud in Freycinet's Voyage, and Pannaria erythro- 

 carpa of Bory in Duperrey's Voyage, seem identical with this species. 



2. Parmelia calicarpa; diffusa, thalli laciniis imbricatis latis rotundatis sinuatis plumbeis 

 rueulosis selatinoso-membranaceis, apicibus convexis, subtus intense fuscis subpubescenti- 

 bus, apotheciis majusculis undulatis runs margine crenato ioliaceo. 



The nearest affinity of this species is perhaps P. colpodes of Acharius, figured by Swartz in his American 

 Lichens, t. 4. f. 3; but the lacinia; of the frond in our plant are much broader, and the margin of the apo- 

 thecia more evident, crenate, lobed, and leafy. 



1. Collema Turneri ; thallo foliaceo membranaceo gelatinoso pellucido badio, lobis 

 irregularibus plicato-undulatis, apotheciis sparsis majusculis convexis centra depressis fuscis, 

 margine amplo rosulato foliaceo. 



This Collema is perfectly distinct from any we have yet seen or can find described. It grows upon the 

 trunks of trees, in large patches of a deep brown colour, and of a thin gelatinous texture, the lacuna; round, 

 much waved, and crisped; the margin of the apothecia is very remarkable, forming a beautiful leafy circle 

 around the fruit, and five or six times broader than the young fructifications. The C. phyllocarpum of 

 Gaudichaud, (Freyc. Voy. p. 204,) from Brazil, differs in the glaucous colour of its foliage, but the margin 

 of the apothecia appears to be the same. 



1. Usnea plicata. Ach. Syn. Lich. p. 305. 



1. Ramalina homalea; thallo compresso ancipiti laevigata nudo ramoso albo pallescente 

 transversim subrimoso, ramis dichotomis attenuatis, apotheciis sparsis centra affixis concavi- 

 usculis subimmarginatis concoloribus. Ach. 



a. cartilagineo-cornea subpellucida, apotheciis valde concavis. 



/3. cartilaginea opaca, apotheciis planiusculis. 



We possess both these varieties from Mr. Menzies: the former, gathered in California, must be v.e» -,,l 

 as the true plant of Acharius. Both are in the present Collection, from Tahiti. 

 Ord. LVL ALG^E. Juss. 



1. Macrocystis Humboldtii. Ag. Syst. Alg. p. 293.-M. pomifera. Bory in Duperrey 

 Voy. v.l. p. 94. t. 9. 



