Ceratophyllum demersum vs echinatum vs submersum?
Posted 21 September 2013 - 12:28 AM
Opinions on what this is?
Posted 21 September 2013 - 10:28 PM
Posted 21 September 2013 - 10:37 PM
I'm seeing Ceratophyllum: demersum, submersum, echinatum, apiculatum, australe, cristatum, floridanum, and llerenae on the USDA plants list. http://plants.usda.gov/java/nameSearch This is going to take me some time to sort through.
Posted 21 September 2013 - 10:42 PM
Posted 22 September 2013 - 09:26 AM
no, that's the only info I had. I think I'm going to go stare at the ID photos until I can tell the species apart by their structures.
C. demersum, submersum, echinatum, and muricatum are the only true species according to the list, the rest are synonyms or subspecies. Grown in the USA? I don't suppose he/she mentioned if it was originally collected from the wild or not?
Posted 22 September 2013 - 05:07 PM
Posted 09 November 2013 - 06:30 AM
while it has longer leaves, they are softer than demersum.
it looks to me like you have demersum. the echinatum seems to have leaves that branch a lot, and i never saw that in demersum or submersum.
Posted 09 November 2013 - 08:37 PM
Posted 10 November 2013 - 02:29 AM
With Hydrilla, water hardness effects the stiffness of the leaves. Hydrilla grown in soft acidic water looks and feels very much like native Elodea, without the characteristic rough feeling that's in every description of Hydrilla I have read. I suspect the texture and leaf length of Ceratophyllum may vary with water chemistry too.
that may be so, but the difference was enough for me to see them when grown in the same tank...
Posted 10 November 2013 - 01:58 PM
Below is an excerpt from Alan Weakley's Flora of the Southern & Mid-Atlantic region, if it helps. The whole document is a free dowload at the UNC Herbarium website.
C. submersum is not in this key, and the USDA Plants database has no record of it in North America (although introduced, undocumented populations are certainly possible).
107. CERATOPHYLLACEAE S.F. Gray 1821 (Hornwort Family) [in CERATOPHYLLALES]
A peculiar and apparently very primitive family, of a single genus and about 6 species, aquatic herbs, of cosmopolitan
distribution. References: Les in FNA (1997); Les (1985, 1986, 1988a,1988b, 1988c, 1989)=Z; Les in Kubitzki, Rohwer, &
Bittrich (1993). Key adapted from Les.
Ceratophyllum Linnaeus 1753 (Hornwort, Coontail)
A genus of about 6 species, aquatic herbs, of cosmopolitan distribution. References: Les in FNA (1997); Les (1985, 1986,
1988a, 1988b, 1988c, 1989)=Z; Les in Kubitzki, Rohwer, & Bittrich (1993). Key adapted from Les.
Identification notes: Ceratophyllum is sometimes mistaken for other, superficially somewhat similar aquatics, such as Cabomba
(Cabombaceae), Utricularia (Lentibulariaceae), and Myriophyllum (Haloragaceae). Cabomba has the leaves opposite (rather than whorled),
dichotomously divided (like Ceratophyllum), but the divisions lacking the marginal denticles of Ceratophyllum, and on a 1-3 cm long petiole (vs.
sessile or on a petiole 0-2 mm long). Utricularia has the leaves sometimes dichotomously divided, but the divisions are usually irregular, the
leaves are alternate (in most species), and bladder traps are present. Myriophyllum has the leaves pectinately rather than dichotomously divided.
1A Largest leaves forking 1-2× (count branching-nodes from the base of the leaf to the tip of the most-forked division); leaves coarse-textured,
stiff, the marginal denticles usually strongly raised on a broad base of green tissue; achene margin wingless, with 2 basal spines or tubercles
(these rarely absent), otherwise entire (lacking marginal spines) ........................................................................................................ C. demersum
1B Largest leaves forking 3-4× (count branching nodes from the base of the leaf to the tip of the most-forked division); leaves fine-textured,
flaccid, the marginal denticles not raised on a broad base of green tissue, sometimes obscure or obsolete; achene margin winged, with 2-20
lateral spines 0.1-6.5 mm long (occasionally spineless), with 2 basal spines (these rarely absent). ..... 2
2A Achene body (excluding the spines) 3-4.5 mm long; first leaves of the plumule simple; [Coastal Plain, NC southward] ............... C. australe
2B Achene body (excluding the spines) 4.5-6 mm long; first leaves of the plumule forked; [widespread] ..................................... C. echinatum
Ceratophyllum australe Grisebach. Cp (GA, NC): ponds, pools, slow-moving streams; rare (NC Watch List). May-
September. Se. NC south to s. FL and panhandle FL, and in the West Indies; also in s. Mexico, Central America, n. South
America, with apparent disjunctions in c. South America and the Galapagos Islands. Les treats this taxon as a subspecies of the
Old World C. muricatum. Because of their allopatric distribution on separate continents and relative morphological
distinctiveness (as shown by Les), I prefer to recognize them at the species level. [= Ceratophyllum muricatum Chamisso ssp. australe
(Grisebach) Les – FNA, K, Z; < C. muricatum Chamisso – GW (also see C. echinatum)]
Ceratophyllum demersum Linnaeus, Coontail. Cp (DE, GA, NC, SC, VA), Mt (GA, VA, WV), Pd (DE, VA): ponds,
pools, slow-moving streams; common (uncommon in GA, NC, SC, VA, and WV). May-September. Newfoundland west to AK,
south to s. FL, TX, CA, and south through the West Indies and Central America to South America. [= RAB, C, F, FNA, G, GW, K,
W, S, Z]
Ceratophyllum echinatum A. Gray in Torrey & A. Gray. Cp (DE, NC, SC, VA), Mt (GA, VA, WV), Pd (VA): ponds,
pools, slow-moving streams; uncommon (rare in WV). May-September. Newfoundland west to Ontario and n. MN, south to c.
peninsular FL and e. TX; also in British Columbia, WA, and OR. [= RAB, C, F, FNA, G, K, S, Z; < C. muricatum Chamisso – GW(also see C. australe); = C. submersum Linnaeus var. echinatum (A. Gray) Wilmot-Dear]
Posted 10 November 2013 - 06:00 PM
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