566 



NATURAL HISTORY 



balloon or an irregularly oval sac, ranging 

 in size from the dimensions of a robin's egg 

 to those of a hen's egg, and filled with a 

 fluid protoplasm, is often found washed up 

 on beaches in the West Indian region and 

 is, in Bermuda at least, often referred to 

 as "sea bottles." Dark green and iridescent 

 in life, it becomes clear and translucent 

 after being killed and exposed to the light 

 for a time and may be as attractive then 

 as when living. Children sometimes pick 

 it up on the beaches and by skilfully 

 exerted pressure playfully squirt the liquid 

 contents into each other's faces. These 

 little "bottles" grow in shallow water 

 mixed in with seaweeds of the soft mossy 

 kinds or under shelving rocks near the low- 

 water line. Another kind of Valonia, con- 

 sisting of somewhat smaller ovoid or bottle- 

 shaped segments that branch and cohere 

 in large masses, is often beautifully iri- 

 descent and very attractive when seen 

 growing in the water. 



It is in the large group of marine plants 

 known nontechnically as the red algae that 

 we find the greatest variety in the tropics, 

 although as individuals the "reds" are 

 rarely so numerous or so conspicuous as are 

 many of the "browns" and "greens." Many 

 of the most interesting and beautiful of 

 the "reds" are so small that their wondrous 

 symmetry and beauty are revealed only to 

 the user of a hand lens or a compound 

 microscope. Several are so delicate or 

 have such a soft gelatinous texture that 

 when floated out on paper and dried under 

 pressure they adhere so closely to the paper 

 and have so little substance that they are 

 sometimes taken for paintings by those 

 who do not stop to realize that no human 

 hand could trace lines of such delicacy and 

 symmetry as these "flowers of the sea" 

 often possess. One of the coarser red sea- 

 weeds of the tropics, Bryothamnium tri- 

 quetrum, looks a little more like some 

 land plants. The main axes have three 

 rows of short toothed or fringed branch- 

 lets, giving these axes a three-angled or 

 three-winged effect. The individual plants 

 form dense clumps one or two feet in 

 thickness, but they sometimes grow asso- 

 ciated in large numbers, forming extensive 

 beds. 



The red algae, like the greens and the 

 browns, contain chlorophyll, the green color 

 substance common to plants in general, but 



they have also another pigment that modi- 

 fies or obscures the green, so that the plants 

 appear to be of some shade of red, pink, or 

 purple, or sometimes almost black. The 

 red pigment is soluble in fresh water, and 

 the green is not, so that red seaweeds 

 washed up on the beach and exposed to 

 rain often become green or show zones or 

 spots of green in the more exposed parts. 

 On the other hand, the green is soluble in 

 alcohol while the red is not, so that the two 

 pigments may be easily separated. The 

 red algae that are really and strikingly red 

 are, with few exceptions, inhabitants of 

 deeper water than the greens and the 

 browns and are usually collected by dredg- 

 ing—or by being found washed ashore, par- 

 ticularly after a storm. 



Several kinds of red algae as well as 

 of "browns" are extensively used by the 

 Chinese and Japanese as articles of food. 1 

 The agar-agar of commerce, derived from 

 red algae, is a food in the Orient, but is 

 known in America best as a nutrient me- 

 dium for laboratory cultures of bacteria 

 and fungi. Another product of red sea- 

 weeds, known as "funori," is manufac- 

 tured by the Japanese to the amount of 

 two or three million pounds a year and is 

 used by them for sizing for cloth, for 

 which purpose it seems to have certain ad- 

 vantages over sfarch. Most of these ma- 

 rine algae from which the Japanese derive 

 products that sell for several millions of 

 dollars a year have close relatives in 

 American waters, but apart from the re- 

 cent development of the kelp potash in- 

 dustry in California and the use of sea- 

 weeds as a fertilizer for the land by 

 farmers living in the vicinity of the sea, 

 the inhabitants of the United States have 

 thus far made little practical use of the 

 plant life of the ocean. 



On the coast of Massachusetts the Irish 

 moss or carrageen (Chondrus crispus i 

 used for making sea-moss jellies or pud- 

 dings, is collected to the value of a few 

 thousand dollars a year, and the "dulse" 

 (Elwdymenia palmata), which is eaten raw 

 as a sort of salad or relish, is gathered in 

 still smaller quantities and offered for sale 



1 See paper, by the writer, on "Some Economic 

 Uses and Possibilities of the Seaweeds." Journal 

 of the New York Botanical Garden, XVIII, 1917, 

 pp. 1-15. 



