This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1892 edition. Excerpt: ...manner; but it is not till a later stage in its development that the manner in which the mature frond is built up is easily observed. At first the thallus consists of rows of rose-coloured cells arranged in filaments which, by their excessive branching in one plane, form a network, and finally a more or less ...
Read More
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1892 edition. Excerpt: ...manner; but it is not till a later stage in its development that the manner in which the mature frond is built up is easily observed. At first the thallus consists of rows of rose-coloured cells arranged in filaments which, by their excessive branching in one plane, form a network, and finally a more or less compact pseudo-parenchymatous membranous expansion, which being confined between the outer layers of the thick compound cell-wall of the Cladophora, and frequently entirely surrounding the cells of the host-plant, assumes, of course, the form of a hollow cylinder. On examining one of these strata it is at once obvious that it is composed of cells arranged in filaments of two sorts--the primary and the secondary filaments. The primary filaments are composed of long cylindrical cells, and extend straight forward for a considerable distance either singly or in close parallel rows of from 2 to 8 (usually 3 or 4) threads: not infrequently, however, after continuing in company for some distance, the filaments of which a group is composed separate again and diverge in opposite directions, each continuing its course alone or joining with other filaments to form a new group. The very much and irregularly branched secondary filaments, on the other hand, are composed of short very variously shaped cells which arise laterally from the primary filaments. Where a number of primary threads run side by side in close proximity they form, as it were, one filament, the secondary branches arising only from those which form the border, and from that side of them which is not contiguous to the other filaments of the group: thus where five threads run in parallel rows the three middle ones are unbranched, lateral branches arising from the two outer ones on that...
Read Less