. The algae. Algae. 90 THE ALGAE and although no sexual fusion has been seen as yet, nevertheless meiosis occurs in V. utricularis at swarmer formation. The plants are therefore presumably diploid, a condition that is also character- istic of most of the Siphonales. The reproductive cells may encyst. Fig. 49 Valonia. A, young plant of V. ventricosa. B, young plant of V. ultricularis ( x 1-4). C, adult plant of same, m = marginal cell. D, plant of V. macrophysa ( xo-8). E, rhizoid of V. utricularis. F, rhizoids from marginal cells at base of vesicle of V. ventricosa. G, single marginal cell and
. The algae. Algae. 90 THE ALGAE and although no sexual fusion has been seen as yet, nevertheless meiosis occurs in V. utricularis at swarmer formation. The plants are therefore presumably diploid, a condition that is also character- istic of most of the Siphonales. The reproductive cells may encyst. Fig. 49 Valonia. A, young plant of V. ventricosa. B, young plant of V. ultricularis ( x 1-4). C, adult plant of same, m = marginal cell. D, plant of V. macrophysa ( xo-8). E, rhizoid of V. utricularis. F, rhizoids from marginal cells at base of vesicle of V. ventricosa. G, single marginal cell and rhizoid (r) of K. ventricosa. H, V. utricularis fruiting. I, V. utricularis^ germinating swarmer. (B, D, after Taylori rest after Fritsch.) themselves, and it has been suggested on this evidence that the plant is a colonial aggregate of coenocytic individuals resulting from the retention of cysts that have developed in situ. The correct- ness or otherwise of this interpretation can only be obtained through a better knowledge of their phylogenetic history and the repro- ductive processes of other members of the group. REFERENCES General Chapman, V. J. (1954), Bull. Torr. Bot. Club, 81 (i), 76. Egerod, L. E. (1952). Univ. Cal. Pub. Bot., 25, p. 325. Feldmaruij J. (1938). Rev. Gen. Bot., 50,57. Spongomorpha Fan, K-C. (1959). Bull. Torr. Bot. Club, 86 {i), Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Chapman, V. J. (Valentine Jackson), 1910-. London, Macmillan; New York, St. Martin's Press
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