Those pretty little 'palm trees' are the dreaded archegoniophores of the
invasive _Marchantia polymorpha_! Beware! If you though the prolific
gemmae cups were effective at spreading the brood, just wait till those
archegoniophores open their bomb bays loaded with spores!
Look around your collection and you may find both palm trees (archegonio-
phores) and umbrellas (antheridiophores). The antheridiophores produce
the sperm cells which must swim across to another plant bearing
archegoniophores, and then swim up the stalk of the archegoniophore
to ferilize the egg cells nestled under the "palm fronds". The zygote
develops into the sporophyte, which is little more than a cluster-bomb
full of spores.
Really though, liverworts are at least as interesting as another
variety of Drosera spathulata. Don't kill them, collect them!
Michael
(PS. about my reference to carnivorous (man-eating!) liverworts...
that post was just a joke! :-)
(PPS. anyone got hornworts _Anthoceros_, _Notothylas_, Dendroceros_, or
_Megoceros_ in their weed collection?)