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Re: ceratopteris deltoidea

Arthur, the reason your google search brought up nada in your search for
"Ceratopteris deltoidea" is because apparently, there isn't any such species
recognized, at least, not any more. I did find a reference listing (March 3,
1997 - Ecology Section - National Wetlands Inventory - US Fish and Wildlife
Service) of wetland plants which lists Ceratopteris deltoidea Benedict and
C. siliquosa (L.) Copeland both as synonyms for the valid species C.
thalictroides (L.) Brongn. This listing is "national" in scope (for the
U.S.). The master list from the same year lists C. gaudichaudi Brongn. in
Hawaii, and C. pteridoides (Hook) Hieron., C. richardii Brongn. and C.
thalictroides (L.) Brongn. as being found in the Southeast part of the U.S.,
all as obligatory wetland species. There is an asterisk next to the name of
C. gaudichaudi Brongn., but I don't know the signifigance of the symbol as
it isn't explained in the document. As far as I can tell, there isn't a "C.

Maybe someone, at some time, gave a specimen the species name "deltoidea"
but it looks like it was subsequently found to be thalictroides. If the name
deltoidea was validly published and later found to be describing an already
known species, it would become a synonym.

Robert M. Lloyd (1974, 1993) recognized 4 species of Ceratopteris - C.
thalictroides, C. richardii, C. pteridoides and C. cornuta. He said that C.
thalictroides is widely distributed in tropical regions and is a polymorphic
species (different plants can exhibit different growth patterns even though
they are all the same species). C. pteridoides and C. cornuta are similar to
one another but distinct from C. thalictroides, with C. pteridoides limited
to South and Central America and C. cornuta mainly confined to distribution
in mainland Africa. C. richardii looks like C. thalictroides but has 16
spored sporangia while C. thalictroides has 32 spored sporangia (not
something you are likely to be able to tell for yourself). Natural hybrids
between species do exist (Lloyd 1993), so it can get really complicted to
say what species a particular specimen belongs to. C. richardii is widely
used as a "model plant" in schools and is called "C-Fern"

Karen Randall is the only person I know of who has a sample of C.
pteridoides - she collected it on one of her trips to the Amazon and
described it in one of her columns in Aquarium Frontiers. Most of the
"broadleaf" floating forms of Water Sprite in the hobby are probably C.
cornuta, with the finer leaved rooting plants being C. thalictroides. In her
article, Karen also mentioned another growth form of Water Sprite, which is
much finer than the regular C. thalictroides. This is usually referred to as
C. siliquosa but the validly of the name is questionable, with most
references showing it as a synonym of C. thalictroides. Whatever it is
called, it IS different and I have seen it available for sale at various
times in the past. Whenever I have grown this finer leaved form I have
noticed that it will throw up emergent leaves after a while and it can get
very big.

For all its simplicity in cultivation, Ceratopteris has been confounding
scientists for years. For a long time, it was placed in its own family,
Parkeriaceae Hook, but the latest edition of the International Code of
Botanical Literature says that it should be placed in the family Adiantaceae
Newman, because the name Parkeriace Hook was not validly published and the
name Adiantaceae has been conserved over Parkeriace Hook. Other sources
(Tropica among them) claim that Ceratopteris belongs in the family
Pteridaceae. The NCBI Taxonomy Browser, which is based upon DNA sampling,
follows this placement.

James Purchase