156 A CONTRIBUTION TO, ETC. 



of the red series, although many kinds are furnished with a double 

 system of fructification, yet it is generally considered that the 

 one is as capable of producing a new plant as the other. A late 

 writer on British sea-weeds remarks : " The greater part, if not 

 all, of the red series is furnished with this double fructification, 

 the primary, or capsular, on one plant, and the secondary, or 

 granular, on another plant. Though the capsules of two different 

 genera and species bear no resemblance to each other, yet there 

 are many modifications of shape, so that they are at once like and 

 unlike, and to become acquainted with the minor differences re- 

 quires time and attention." 



Persons not accustomed to searcK into the works of nature will 

 be astonished to find a very extensive field for investigation, in 

 the flora of the deep. During Dr. Harvey's botanical voyage to 

 the Australian colonies he collected no less than 20,000 specimens 

 of six hundred species of sea-weeds, and he estimates the number 

 of species of Algae dispersed along our coasts at nearly 1000 ! 

 Some of the species so beautifully figured and described by that 

 eminent phycologist, are indeed very rare, and perfect specimens 

 of them can seldom be procured without dredging ; but some of 

 the more common forms are frequently cast upon our shores. It is 

 to these forms that I wish to direct attention in the present com- 

 munication, because it is almost impossible to walk along the 

 shore without noticing some of them, and I think that the study 

 of them affords a very suitable introduction to the investigation 

 of the marine flora of Australia in general. 



Of the Melanospermese, which are common at Manly Beach, 

 and other places on the coast, the following genera can scarcely fail 

 to be noticed, even by a casual observer, viz., Sargassum, Cystopliora, 

 Phyllospora, Hormosira, Laminaria, Padina, Zonaria, and Dietyota. 

 They are all of a brown or olive-brown colour, and after a storm 

 large masses of the commoner kinds may be seen strewed along the 

 beach. The genus Sargassum prevails over a wide extent of ocean, 

 but from the circumstance of its having been early observed to 

 be abundant in the Gulf of Mexico, it has very generally been 

 called the " gulf-weed." The fronds of this genus are leaved, 

 the leaves stalked, and generally with a mid-rib : air-vessels 

 simple, axillary, and stalked : receptacles small, linear tubercu- 

 lated, mostly in axillary racemes, seeds in distinct cells. Many 



