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IX. ALGAJ. 
Order IX. ALGriE. 
Plants consisting either of simple cells or of threads of cells, or of cellular 
fronds, almost invariably aquatic and chiefly marine ; usually fixed by a 
root (which does not nourish the plant) ; imbibing nutriment through their 
whole surface ; supposed to be always 2-sexual, though this is not yet demon- 
strated in many genera ; very many are propagated also by division of the 
plant, or by buds from it, or by the division of individual cells. Keproduc- 
tive organs of various kinds, on one or on different plants, naked on the 
surface of the frond, or buried in its substance, or contained in proper cavi- 
ties or sacs (conceptacles), which again may either be superficial or immersed, 
or contained in special branches of the frond. Female fructification, consist- 
ing of simple or compound spores, which originate as cells that are fertilized 
by antherozoids, or by the contact of other cells that transmit the fertilizing 
matter; these spores may be naked or clothed in a gelatinous envelope, or 
contained in tubes ( asci ). Male fructification essentially and usually of 
microscopic antherozoids, contained in sacs or cells, and consisting of a 
nucleus with vibrating threads of infinite delicacy. In the unicelhdar species 
and those formed of threads of cells, the sexes may be represented by a single 
cell that divides in the middle, or by 2 cells, from the union of which the 
spore is developed. 
The vast Order of Algae is now often, regarded as consisting of several Orders, which I 
have here distinguished as Suborders, there being so many genera whose position is doubt- 
ful amongst these Suborders, and all being so obviously modifications of one common plan, 
that I think Atgce may still be regarded with propriety as a Natural Order, equivalent to 
such others as Graminece , Lichens , Fungi, Composites, etc. Though so different in habit, 
locality, aud general appearance from Lichens, the absolute difference between these Orders 
is reduced to a very little in Lichina and others. With Fungi, also, their affinity is very 
close ; and, finally, some of the unicellular’ and filamentous genera present appearances at 
certain stages of their development that render it impossible to say whether they should be 
referred to the animal or vegetable kingdom. 
Marine Algae occur at all depths in the ocean between high tide or its spray, and upwards 
of 100 fathoms, but they abound most between tidal limits or just beyond them. As a 
rule, the bright green kinds occur nearest to high-water mark aud extend to fresh water ; 
the dark olive-green abound between tidal marks; and the bright red affect deeper water; 
but to this there are many exceptions. The great seaweed that forms olive-green floating 
patches girdling the New Zealand harbours \Macrocystis pyrifera) I have seen off the Crozet 
Island, where the soundings gave 40 fathoms, and which there is reason to suppose may 
hence have been 700 feet long (FI. Antarct. 4(i4). 
Iodine, kelp, aud soda are the products of this Order, which also contains several plants 
that are eatable in a raw or cooked state, as Luver and Dulse, and a copious jelly in the case 
of the “Carrageen moss” of Ireland, the produce of species of Chondrus, Gracilaria, and 
Gigartina. Others are used as manure and as fodder for cattle ; a valuable cement is made 
by the Chinese from Gracilaria tenax ; aud knife-handles of the stems of various Larninariece 
by whalers and others. 
New Zealand is very rich in Algae ; its deep waters aud quiet sounds especially abound in 
species of this interesting and beautiful Order, which have been most admirably collected by 
my old friend Dr. Lyall. Amongst the microscopic unicellular and filamentous tribes, there 
must still be many hundreds, perhaps thousands, of species to be discovered in the sea and in 
freshwater ponds, rivers, and the islands. These are subjects of special research, far beyond 
the scope of a student of general botany, or of a handbook like the present. To study them 
advantageously would require a powerful microscope and a very good library, infinite 
patience, and considerable manual skill. To those who would undertake these branches I 
