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Cryptogams or Flower less Plants — Algce . 
I. MELANOSPERME^E or FUCOIDE.E. 
Example. —Wrack or Bladder-wrack (Fucus vesiculosus and allies), covering rocks between tide marks, very 
abundant upon the British coast. The long leathery, repeatedly-forking fronds are provided with large embedded, 
oblong, inflated air-vesicles which serve as floats. In Gulf-weed ( Sargasswm ) the air-vesicles are globose and 
distinctly stalked in the axils of flattened leaf-like branches. 
The reproductive, organs are contained in the thickened or club-shaped extremities of the divisions of the frond, 
which may be recognised by their paler colour and the presence of numerous minute pore-like orifices on the surface 
visible.to the naked eye. These orifices communicate with minute cavities lined either with sporanges or with 
antheridia, or, in some species of Fucus, with both in the same cavity. The sporanges are oblong double-walled 
cells projecting into the cavity, and attached to its side. Each sporange contains 2, 4, or 8 spores, which when 
ready for fertilisation are liberated by the rupture of the membrane of the sporange. 
The antheridia are very minute cells borne upon branching filaments, attached to the sides of the minute 
cavities similarly to the sporanges. The contents of each antheridium becomes resolved into a number of 
excessively minute, rapidly motile, club-shaped antherozoids, each provided with 2 cilia and usually an orange- 
coloured speck. They are liberated, like the spores, by rupture of the containing cell, and their presence is easily 
detected in early spring, if examined after exposure of a few hours to the air, by the orange-coloured exudation, 
from the pores of the cavities containing antheridia, due to crowds of minute antherozoids. The spores are fertilised 
by contact of the antherozoids, develop a membranous coat, and then commence to germinate. 
II. RHODOSPERMEiE OR FLORIDE^E. 
The species are usually very much smaller than the Melanosperms. Many of the rose-red leaf-like or delicately 
divided species common upon the sea-shore, especially in rocky tidal pools, are familiar to all frequenters of the 
coast. The modes of reproduction of the Red Sea-weeds are very varied, and would appear to include multiplication 
by means of specially developed bud-cells or gemmules as well as reproduction by spores fertilised by antheridia. 
In the species in which a true sexual reproduction has been observed the spores are fertilised by antherozoids, 
destitute of cilia.and of the power of locomotion liberated from an antheridium, through a long slender filamentous 
prolongation of its cavity. In the true Corallines ( Corallina ), frequent in tidal pools, the thallus is transversely 
jointed, and rigid from the deposition of carbonate of lime in its substance. 
