Ser. Melanospekme^. Laminar iaeece. 



Plate CCII. 



MACROCYSTIS PYRIFERA, 47.; 



Var. DuBENii, Aresch. 



Gen. Char. Root branching. Stem filiform. Leaves simple, formed by 

 the continual splitting of a primary terminal leaf, developed in se- 

 eund order along the lengthening stem, petiolate, having an air-vessel 

 in the petiole. S]jores forming irregular, superficial, cloud-like patches 

 on small radical leaves, ellipsoidal, with hyaline perispore, surrounded 

 by densely packed, inarticulate, clavate paranemata. — Macrocystis 

 [Ag.], from fiaKpo<;, large, and KvcrTt<i, a vesicle. 



Radix ramosa. Caulis Jiliformis. Folia simplicia, fissiira adscendenti fol'd 

 termiiialis orta, in caule elorujato secunda, basi vesiculifera ; radlcalla evesi- 

 culosa, petiolis dichotomis. Spor(B soros nebulosos infoliis radicalihus siiper- 

 f dales formantes, elUpsoidece, perisporio hyalino, paranematibiis inarticiilatis 

 clavatis circumdaice. 



Macrocystis pyrifera, var. Duhenii ; stem filiform ; vesicle cylindrical- 

 clavate, 4-5 times as long as broad ; leaf linear-lanceolate, undulate- 

 furrowed. 



M. pyrifera, var. Dubenii; caule fillformi ; vesicula cijUndraceo-clavata diametro 

 4;-o-plo long lore ; folio linear i-lanceolato undulato-sulcato. 



Macrocystis Dubenii, Aresch. Icon. Phyc. p. 5. t. 10. 



Hab. Outside Port Phillip Heads, abundantly. (Other varieties found on 

 the south coast of Australia, to the east of Cape Northumberland, 

 and in Tasmania.) 



Geogr. Distr. Macrocystis pyrifera, in one or other of its forms, is found exten- 

 sively throughout the Southern Ocean, south of the tropic, and along the 

 whole west side of America as far north as Unalaschka and Siteha. Indian 

 Ocean, Sundevall, Jide J. Agardli. Not found in the Atlantic? 



Descr. (Var. Dubenii.) Root extensively branching, throwing up many stems. 

 Sterns filiform, 50-100 feet long or more, 2 hues in diameter, producing 

 leaves in secund order at distances of from 3-12 inches apart, according to 

 the portion of the stem examined. Terminal /eo/ narrow, ensii'orm, hooked 

 inwards at the point, obliquely ovate at base, and there splitting, bordered 

 with long, slender ciliary processes. Lateral leaves 2-4 feet long, 2-3 

 inches in breadth, corrugated longitudinally into parallel ridges and furrows, 

 which are more apparent on the dried specimen, tapering to both ends, and 

 bordered with slender ciUa, ^-1 inch apart, resides, when young, almost 



