Ser. Chloi:ospermk.k. Fam. Valoniacea. 



Plate XXII. 



PENICILLUS ARBUSCULA, Mont 



Gex. Char. Boot fibrous, much branched, matted. Frond stipitate, 

 dendroid. Stipes erect, terete, incrusted, composed of numerous uni- 

 cellular, longitudinal, cylindrical, branching, interwoven filaments, and 

 crowned with a dense pencil of confervoid, articulated, free or co- 

 hering ramelli. Cells covered with a porous, calcareous pellicle. — 

 Penicillus {Lam.), from penicillus, a painter's brush, which these 

 plants resemble. 



Radix fibrosa, ramosissima, im.plica.ta. Frons stipitata, dendroidea. Stipes 

 erectus, teres, incrustatus, ex fills numerosis unicellularibus longitudinalibua 

 cylbidraceis ramosis intertextis formatus, ramellis confervoideis dense fascicu- 

 latis nunc liberis nunc in lamellas coharentibus coronatus. Cellulce pellicula 

 calcared porosd corticatce. 



Penicillus Arbuscula ; stipes short, terete, smooth ; capitulum dense, 

 fastigiatej filaments free, dichotomous, moniliform below, above coin- 

 posed alternately of globose and cylindrical cells, the latter about 

 3-4 times as long as broad. 



P. Arbuscula; stipite brevi tereti Icevi ; capitulo dense fastigiato ; fills lihi-ri* 

 dichotornis infra moniliformibus supra ex cellulis nunc globosis nunc cglin- 

 draceis diametro 3-4-plo longioribus suballernis formatis. 



Penicillus Arbuscula, Mont. Fog. Pol. Bud, p. 25. t. 14./. 4 ; Sglloge,p. 451. 

 Harv. Trans. R. I. Acad. v. 22. /;. 564. 



Corallocephalus Arbuscula, Kiitz. Sp. Alg.p. 506. 



Hab. On sand-covered rocks, between tidemarks. Abundant on some 

 of the reefs at Eottnest Island, Western Australia, W. H. II. 



Geogr. Distr. At the Island of Toud, D' Urville. 



Descr. Roots, mass of excessively branched, interwoven fibres, deeply descending 

 into the sand. Stem, when full-grown, about an inch in length, 2-3 lines 

 in diameter, terete or somewhat compressed, either cylindrical or widened 

 upwards, composed of densely interwoven filaments, and coated with a 

 smooth, calcareous crust. In the yoxmg frond the stipes consists of but two 

 or three filaments, and a strata of the frond occurs in which there is no 

 stipes, but the moniliform, confervoid filaments arise directly from the 

 matted root-fibres. In ordinary specimens the stipes is crowned with a 

 lar • e, dense, globular tuft of slender setaceous filaments, 1-2 inches long, 

 and repeatedly dichotomous. These filaments (or ramelli) are articulated ; 

 the articulations variable in length. In the lower part all are generally 

 globose, with constricted nodes ; in the upper, globose and cylindrical cells 

 irregularly alternate with each other. As in all the genus, the cell-walls 

 are coated with a thin pellicle of carbonate of lime, pierced with pores, 



