Directory       News       Site Map       Home
         
    Jepson eFlora: Taxon page
Key to families | Table of families and genera

Previous taxon Indexes to all accepted names and synonyms:
| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Previous taxon

CERATOPHYLLACEAE HORNWORT FAMILY

Donald H. Les

Perennial herb, submersed aquatic; overwintering on bottom as detached, dense shoot tips (winter buds); roots 0; monoecious; water-pollinated. Stem: flexible with water currents, internodes clustered near tip. Leaf: whorled, generally compound, forked; segments linear, toothed; stipules 0; petiole 1–2 mm, translucent. Inflorescence: reduced axillary cymes generally near shoot tips, ± sessile, 1–several per node, generally staminate below, pistillate above, or sometimes mixed at a node; flowers 1–3 per cyme but appearing to be 1 subtended by calyx-like whorl of 8–15 bracts, bracts linear, leaf-like, fused at base, toothed at tip, persistent in fruit. Flower: unisexual; perianth 0; staminate round-topped, stamens 3–50, spirally arranged, anthers ± sessile, exserted from bracts, pollen shed underwater; pistillate of 1 simple, ovoid pistil, ovary superior, chamber 1; placenta pendulous; style elongate, spine-like, with decurrent groove; stigma pocket-like, at style base; ovule 1. Fruit: achene, tubercled or not, spines 0 or elongate, basal, facial, marginal or stylar; lateral margin winged or not.
1 genus, 6 species: ± worldwide. [Les 1997 FNANM 3:81–84] —Scientific Editor: Thomas J. Rosatti.

CERATOPHYLLUM HORNWORT
(Greek: horn leaf, for antler-like appearance) Ceratophyllum grown as ornamental or for oxygen generation in aquaria, garden ponds. Leaves, fruit eaten by migrating waterfowl. Vigorous growth (even of native species) can result in weedy infestations.

C. demersum L.
NATIVE
Stem: 1–3+ m, glabrous, limp, suspended by water, brittle, branches 0–3 per node. Leaf: 3–11 per node, 0.8–3 cm; segments 2–4, with 2 rows small teeth distally, 1 multicellular, glandular appendage at tip. Inflorescence: uncommon. Flower: staminate 2–5 mm, stamens pink to ± red; pistillate 1–2 mm, pistil generally ± yellow, margins red-tinged or not, style generally 1 mm. Fruit: 3.5–6 mm (except spines), dark green to red-brown, generally tubercled, base with 2 tubercles or 2 spines, margin spineless, wingless; spines 0.1–12 mm, stiff, bases generally webbed; style persistent on fruit, stiff, erect, 0.5–14 mm. Seed: cotyledons large, fleshy; terminal bud highly developed; first leaves simple, opposite, awl-like.
2n=24,38,40,48. Common. Ditches, lakes, ponds, pools, slow watercourses; water 0.1–4 m deep, fresh to ± brackish, medium to high nutrient levels, acidic to alkaline (pH 5.9–9.4) but generally alkaline (pH > 7); generally < 1700 m. California (except Cascade Range Foothills, Tehachapi Mountain Area, Channel Islands, White and Inyo Mountains, Desert Mountains); common worldwide. Plants self-fertile; populations generally > 50% staminate. Jun–Aug [Online Interchange]
Unabridged note: Plants with fruit having basal tubercles instead of spines were named Ceratophyllum apiculatum Cham., but such variants occur commonly and sporadically throughout sp. range and do not merit taxonomic recognition.

Previous taxon: Ceratophyllum
Next taxon: Acanthaceae

Contact/Feedback

Name search

Citation for the whole project: Jepson Flora Project (eds.) 2013. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on Nov 24 2014
Citation for this treatment: [Author of taxon treatment] 2013. Ceratophyllum, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=18711, accessed on Nov 24 2014

Copyright © 2014 Regents of the University of California
We encourage links to these pages, but the content may not be downloaded for reposting, repackaging, redistributing, or sale in any form, without written permission from The Jepson Herbarium.


Geographic subdivisions indicated for the distribution of Ceratophyllum demersum Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
READ ABOUT YELLOW FLAGS
map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

View elevation by latitude chart
Data provided by the participants of the Consortium of California Herbaria.
View all CCH records

 

CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.