Dube M A
Department of Biology, Western Washington State College Bellingham, Washington 98225.
J Phycol. 1967 Jun;3(2):64-73. doi: 10.1111/j.1529-8817.1967.tb04632.x.
Results of the study of Monostroma fuscum from Son Juan Island, Washington, fully support the separation of the species M. fuscum from Monostroma sensu Wittrock into a taxon including M. obscurum. It would appear from this and previous studies that the M. obscunim-M. fuscum complex is clearly Ulvacean. The characteristics of the complex include (1) alternation of morphologically similar haploid and diploid generations; (2) production of biflagellate gametes and quadriflagellate zoospores; (3) a uniseriate form in early ontogeny; (4) thallus development progressing through a vesicular stage that, as a result of localized degenerative processes, opens at a size of less than I cm into a monostromatic blade; (5) cells elongated perpendicular to the plane of the thallus and with rotund-truncate ends: (6) a single elongate plastid, thickened at the opposite poles of the cell and thinner in the equatorial region of the cell; (7) a thallus composed of cells with relatively inelastic walls; and (8) discrete discharge pores. The chromosome number of Monostroma fuscum is n =9. The first division of the zoosporangium nucleus is meiosis I.
对来自华盛顿州圣胡安岛的褐礁膜（Monostroma fuscum）的研究结果，充分支持将褐礁膜物种从维特罗克广义礁膜属（Monostroma sensu Wittrock）中分离出来，归入一个包含暗礁膜（M. obscurum）的分类单元。从这项研究以及之前的研究来看，暗礁膜 - 褐礁膜复合体显然属于石莼科（Ulvaceae）。该复合体的特征包括：（1）形态相似的单倍体和二倍体世代交替；（2）产生双鞭毛配子和四鞭毛游动孢子；（3）个体发育早期为单列形式；（4）叶状体发育经过一个泡状阶段，由于局部退化过程，在小于1厘米大小时开口形成单层叶片；（5）细胞垂直于叶状体平面伸长，末端圆形 - 截形；（6）单个细长质体，在细胞相对两极加厚，在细胞赤道区域变薄；（7）叶状体由细胞壁相对无弹性的细胞组成；（8）离散的排放孔。褐礁膜的染色体数为n = 9。游动孢子囊核的第一次分裂是减数分裂I。
