Zea mays

1.6
1.6 L}'copusicon e$culentum (tomato} fruit. In T$ the
numerous seeds (1) are seen attached to axial placentas (2)
and embedded in juicy tissue derived from placental tissue.
The four locules indicate that the fruit developed from an
OV3£}" of four fused carpels. In the external view the
remains of the flower stalk and the green sepals (3) are
...isible at irs base; this fleshy fruit developed from a single
superior ovary which was situated alxl\'c the p:rianth.
1 S=h
2 Axial placentas
3 Sepals
1.8 LS of [he heterosporous conc of Selagineffa (a fern
ally). The sporangia are borne in the angle between the
cone: axis and the sporophylls (l). Within the sporangia the
spore mother cells undergo meiosis: the mcgasporangia
comain a few large and thick-walled haploid mq;aspores
(2}, while the microsporangia comain abundant small and
thin-walled mkrospores (3).
Note the small ligules (4) on the adaxial surface of the
sporophylls; this feature shows the affmity of present day
Sdaginella with the fossil Lepidodendron, the dominant
tree of the Carboniferous coal measures. (LM x 35.)
1 Sporophyll
2 Megaspores
3 Microspotes
4 Ligule
1.7 Portion of a withered fenile frond (leaf) of the subnopical
nee feen Dicksoni4 QntQrtiCD. The multitudinous
sporangia on its ahaxial surface have dehisced and shed
billions of yellow, uniform-sized, haploid spores onw the
bench surface.
13
1.7
1.8