BIOLOGY 230 Lecture Notes - Lecture 10: Meristem, Selaginella, Lycopodium
3a. Club mosses!
•The divided apical meristem shows the dichotomous division. The leaves are microphylls,
which means leaves with a single unbranched vein coming from the protostele without a
leaf gap. The yellow bulbed-shaped spore wall contains the unicellular spores. The
sporangia attach to the base of each sporophyll on the upper stem and branches. They
turn yellow as they mature. The yellow spores, when touched, or blown by the wind, are
released. Since a large area of the plant is covered, they can produce a large number of
spores.!
•Not a photosynthetic gametophyte#
3b. Spike mosses (Selaginella)
•The gametophytes of Selaginella are much further reduced than in Lycopodium. They divide
and remain within the spore walls and quickly produce the gametes (see below).
4. Pteridophytes, or ferns
•This group comprises vascular plants that reproduce by spores (not seeds) but have more
complex and generally larger leaves (megaphylls). We will continue the following lab with
examining features of fern sporophytes, but here we will have the opportunity to examine
fern gametophytes
Document Summary
The divided apical meristem shows the dichotomous division. The leaves are microphylls, which means leaves with a single unbranched vein coming from the protostele without a leaf gap. The yellow bulbed-shaped spore wall contains the unicellular spores. The sporangia attach to the base of each sporophyll on the upper stem and branches. The yellow spores, when touched, or blown by the wind, are released. Since a large area of the plant is covered, they can produce a large number of spores: not a photosynthetic gametophyte. Spike mosses (selaginella: the gametophytes of selaginella are much further reduced than in lycopodium. They divide and remain within the spore walls and quickly produce the gametes (see below): pteridophytes, or ferns, this group comprises vascular plants that reproduce by spores (not seeds) but have more complex and generally larger leaves (megaphylls).
