Page:Journal of botany, British and foreign, Volume 34 (1896).djvu/309

 NOTES ON SARCOMENIA MINIATA AG. 283 the tetraspores at the top show signs of division. This explains readily the extreme usefulness of such arrangements as tend to consolidate the stichidia. The cells of the central tube are connected by a very strong strand of protoplasm. The contents of these cells are much more delicate than those of the pericentral tubes, but by the help of this considerable strand of protoplasm they are always easily recognized. Secondary pores and smaller strands of protoplasm connecting the pericentral tubes with each other or with the central tube were also visible. I believe I saw migrating cells as described by Kolderup- Rosenvinge'-' for Polysq)lionia, but I failed to detect a cell-nucleus in the little particles of protoplasm that were lying in the gelatinous layer between the cells. I must therefore leave the question un- settled whether these particles of protoplasm are identical with Kolderup-Rosenvinge's migrating cells. The branching of Sarcomenia miniata is very irregular ; the branches arise, as Agardh has already described, from the middle of the stem. Careful examination shows that they are the result of endogenous growth, as described already by Falkenbergf and Ambronn| for species of the genera Rytiphlcea, Vldalia, Amansia^ and Polyzonia. The central tube pushes a branch between the peri- central tubes, which yield to let the young unicellular branch pass. This cell divides by horizontal walls, the first two segments re- maining naked, the upper ones surrounding themselves in the usual way by pericentral tubes. The pericentral tubes of the stem from which the branch arose give off a few cells that cover the first naked segments of the branch, but otherwise they undergo no further changes. On one specimen only of my whole collection could I detect antheridia. The plantlet bore also cystocarps ; it is therefore monoecious. The antheridia were found at the base of the stem, and consisted of very small leaflets, borne in the usual endogenous way. The lateral tubes of these leaflets are, as in the case of the branches bearing tetraspores, the cells out of which the propagating organs arise. I have not been able to follow the mode of develop- ment from lack of specimens, but figs. 6 and 7 are exact figures of the antheridia as I saw them. I can only suppose that each cell of the lateral tube divides first by a horizontal wall, and that the protoplasmic masses (cf. the figure) seen at the base of a large empty cell are the remnants of the lower or pedicel cells, whose function it probably was to prevent the collapsing of the walls of the cells les Polysiphonia,'' BoU Tidskr. 17 Bd. 1 Heft. Kopenhagen, 1888. t Falkenberg, " Ueber endogene Bildung normaler Seitensprossen in den Gattungen Rytiphlcea, Vidalia, und Amansia" Nachr. der Ges. d. Univ. zu Gottingen, 1869, p. 285. I Ambronn, "Die Art und Weise der Sprossbildung bei den Ehodomeleen Gattungen Vidalia, Amansia, und Polyzonia,^' Verhandl. d. hot. Vereins d. Provinz Brandenburg, 1880, p. 74. u 2
 * Kolderup-Kosenvinge, L., " Sur la formation de spores secondaires chez