Where, as in types like these, the morphological units show an inherent tendency to arrange themselves in a manner which is so far constant as to give characteristic proportions, we may say that there is a recognizable compound individuality. Considering the Thallophytes which grow in this way apart from their kinships, and wholly with reference to their morphological composition, we might not inaptly describe them as pseudo-foliar. § 184. Another mode in which aggregation is so carried on as to produce a compound individuality of considerable definiteness, is variously displayed among other families of _Algæ_. When the cells, instead of multiplying longitudinally alone, and instead of all multiplying laterally as well as longitudinally, multiply laterally only at particular places, they produce branched structures. Indications of this mode of aggregation occur among the _Confervoideæ_, as shown in Figs. 22, 23. Though, in some of the more-developed _Algæ_ which exhibit the ramified arrangement in a higher degree, the component cells are, like those of the lower _Algæ_, united together end to end, in such way as but little to obscure their separate forms, as in _Cladophora Hutchinsiæ_, Fig. 31; they nevertheless evince greater subordination to the whole of which they are parts, by arranging themselves more methodically. Still further pronounced becomes the compound individuality when, while the component cells of the branches unite completely into jointed cylinders, the component cells of the stem form an axis distinguished by its relative thickness and complexity. Such types of structures are indicated by Figs. 32, 33--figures representing small portions of plants which are quite tree-like in their entire outlines. On examining Figs. 34, 35, 36, which show the structures of the stems in these types, it will be seen, too, that the component cells in becoming more coherent, have undergone changes of form which obscure their individualities more than before. Not only are they much elongated, but they are so compressed as to be prismatic rather than cylindrical. This structure, besides displaying integration of the morphological units carried on in two directions instead of one; and besides displaying this higher integration in the greater merging of the individualities of the morphological units in the general individuality; also displays it in the more pronounced subordination of the branches and branchlets to the main stem. This differentiation and consolidation of the stem, brings all the secondary growths into more marked dependence; and so renders the individuality of the aggregate more decided. [Illustration: Figs. 31–36.]