67. The covering of a sorus is called a(n) ____________________.
68. The fern gametophyte is called a(n) ____________________.
69. The type of branching where the stem divided into two essentially equal halves is called
____________________
70. Megaspores are produced in ____________________.
71. The production of two different kinds of spores is a condition known as ____________________.
72. A cone-like structure found in horsetails that bears sporangia is called a(n) ____________________.
73. In horsetails, the ____________________ is the dominant generation.
74. A scale-like structure produced at the base of the leaves of spike mosses is a(n) ____________________.
75. The stem found in quillworts is called a(n) ____________________.