REPORT OF THE CHEMIST 



195 



SESSIONAL PAPER No. 16 



No. 1. Fucus vesiculosus, L. Common Bladder Wrack. — This is one of the larger 

 and commoner sea-weeds. The body of the plant (thalus or 'frond') is dark brown or 

 almost black in colour and much branched, the method of branching being a repeated 

 iorking of a branch or segment into smaller ones. The whole plant may reach a 

 length of three feet and the segments a breadth of two inches. Each branch is a 

 ribbon-like structure with a distinct mid-rib. It is usually provided with prominent 

 air-bladders, spherical or more usually elongated in form, arranged in pairs, one on 

 each side of the mid-rib so as to form two regular rows. 



No. 2. Ascophyllum nodosum, (L), Le Jolis. — This is somewhat similar to the 

 preceding but the branching is more of a feathery (pinnate) type, the thallus branches 

 have no mid-rib and the air-bladders are arranged in a single row along the middle 

 line of each. 



No. 3. Porphyra laciniata, (Lightf.) Ag. — In this species, the thallus is extremely 

 thin and delicate, being almost transparent in places. It is broad and somewhat 

 leaf -like in form, and irregularly slit or indented into a number of lobes ; the margins 

 wavy; the colour bluish or greenish with various shades of brown or red-purple, often 

 becoming violet in drying. The entire plant is from four to six inches in length. 



No. 4. Laminaria longicruris, Dela. Pyl. — This resembles N09. 1 and 2 in being a 

 brown sea-weed but is totally different in form. The frond is a long, flat expansion 

 resembling the blade of a leaf, and supported below by a tough and very flexible stalk. 

 This in turn is attached at its base to a root-like organ. The blade is without any 

 mid-rib or air-bladders and the margin may be more or less wavy. 



Analysis of Fresh Sea-Weed. 



Very considerable differences are to be noted in the water-content, and hence in 

 the ' dry matter,' of these varieties. This is possibly explained in part by differences 

 in the stage of growth or maturity of these sea-weeds at the time of collection. It is 

 of interest to note that while the varieties differ so widely in their organic matter 

 content, they do not show corresponding differences in ash; thus we have, comparing 

 the extremes in organic matter (7-15 and 19-30) a difference proportionately twice 

 that found between the extremes in ash (4-10 and 5-56). We do not find that the 

 percentage of dry matter is any sure indication of relative fertilizing value, for No. 

 4 with 11-7 per cent dry matter contains 1-546 per cent potash, while No. 2 with 24-86 

 per cent, contains less than one-half that amount, namely, -619 per cent potash. This 

 variation will be more apparent when considering the data given in the next table, 

 in which is considered the composition of the dry matter. Of the varieties now com- 



16 — 13J 



