CHARALES, Ica-ri'lez (from Latin chara, some unknown plant), a highly specialized or der of the green ale or Chlorophycacem. By some authorities it is considered as a group the Characem —of rank equal to that of the Chlorophycacem (q.v.). Members of the group are found both in fresh and in salt water. Formerly there were held to be only two genera of Charales, Chara and Nitella, but each of these has been subdivided by recent authorities. All the members of the group bear a strong superficial resemblance to the Archegoniate plants, for they appear to possess stem, leaves and roots. In fact, their general external aspect is that of a small Equssetum. They grow to a height of from three inches to three feet, but the stalk is exceedingly slender, rarely exceeding a fifteenth of an inch in thickness.
Although asexual reproduction by spores is unknown in the Charales, they have several different types of structures which are able to survive after being separated and which de velop into new plants the spring after they leave the mother plant. Sexual reproduction is carried on through extremely complicated or gans whose closest analogues elsewhere are to be found among the brown algae. These or gans, which are differentiated into male and female, are to be found at the points where the so-called leaves give off their leaflets. In cer tain species they are to be found on different plants, but usually the same node bears both the curiously twisted oogonia and the anthe ridia, as the female and male organs are re spectively called. Of all male organs among
plants, the antheridium of the Charales attains the highest degree of complexity.
The female cell or ovum is large and turbid with oil-drops and starch-grains, but the outer end is hyaline. The male cells or spermato zooids are of spiral form and taper, having two cilia at the smaller end. The product of the union of the spermatozooid and the ovum is the fertilized egg-cell or oospore. There is no alternation of generations with n chromosomes and 2n chromosomes to be found in any of the Charales. Nevertheless the oospore does not develop into the plant, but goes through the stage known as the proembryo. In Chara crinita, only the female of which is known, the ovum develops into an oospore parthenogeneti cally, and no chromosome-reduction takes place.
The precise affinities of the Charales are not well known. Their sexual organs are un like those of the other green algae., but closely resemble those of the brown ale, but Chara does not contain a trace of the brown pigment of the latter. The position that has been assigned to them as precursors of the mosses is at least doubtful, although they show a close analogy to the Archegoniates in their karyokinetic processes and in the form of the antherozooids. Consult Allen, cem of North America' (New York 1888); Filarsky, 'Die Characeen> (Budapest 1893).