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Myriophyllum hippuroides
WESTERN WATER-MILFOIL

Higher Taxonomy
Family: HaloragaceaeView Description 

Common Name: WATER-MILFOIL FAMILY
Habit: [Annual, shrub] perennial herb, generally aquatic or semiterrestrial, dioecious or monoecious. Leaf: cauline, opposite, alternate or whorled; submersed blades pinnately divided, segments thread-like; emergent leaves simple, entire to divided. Inflorescence: raceme, spike, or panicle; flowers 1 or clustered, short-pedicelled to +- sessile. Flower: generally unisexual, small; calyx tube short, fused to ovary, lobes 2--4; petals generally 2--4; stamens 4 or 8, filaments generally short; ovary inferior, chambers 1--4, styles 2--4, separate, stigmas generally plumose. Fruit: fleshy or of nut-like mericarps, dehiscent or not. Seed: generally 1 per chamber.
Genera In Family: 6--8 genera, +- 100 species: especially southern hemisphere, some cultivated. Note: Haloragis erecta (Murray) Eichler not naturalized in California.
eFlora Treatment Author: Adolf Ceska & Oldriska Ceska
Scientific Editor: Bruce G. Baldwin.
Genus: MyriophyllumView DescriptionDichotomous Key

Common Name: WATER-MILFOIL
Habit: Plant from rhizomes, occasionally with overwintering buds (late in growing season); occasionally terrestrial. Stem: simple or branched, generally green. Leaf: submersed leaves generally whorled, 3--6 per node; emergent leaves entire to pinnately divided, occasionally bract-like. Inflorescence: generally emergent, spike-like, simple or branched, terminal, flowers in whorls. Flower: proximal pistillate, middle occasionally bisexual, distal staminate; calyx lobes 4; petals generally 4, ephemeral on staminate flowers, minute or 0 on pistillate flowers; stamens generally 8; ovary 4-chambered. Fruit: mericarps 4, nut-like.
Species In Genus: +- 60 species: worldwide. Etymology: (Greek: many leaves, from leaf segments) Note: Myriophyllum specimens best collected in flower or fruit.
Unabridged Note: Plants should be washed first and then "floated" on the herbarium mounting paper in a shallow dish with water [see Ceska & Ceska 1987 Ann Missouri Bot Gard 73:825--827].

Myriophyllum hippuroides Torr. & A. Gray
NATIVE
Habit: Monoecious; winter buds 0. Stem: > 1 m. Leaf: alternate, or whorls of 4--5 with scattered single leaves; submersed leaves > 2 cm, midrib and segments linear, segments < 10 mm, 14--20(40) per leaf. Inflorescence: spike, 3--12 cm, emergent; bracts 5--15 mm, 1--2 mm wide, >> flowers, generally entire to +- toothed.
Ecology: Ponds, small streams; Elevation: < 1100 m. Bioregional Distribution: NCoRO, NCoRI, n SNH, SnJV, n CCo, SnFrB; Distribution Outside California: to southern British Columbia, introduced in Oklahoma, Texas. Flowering Time: Jul--Sep Note: Easily recognized by single leaves originating between whorls.
eFlora Treatment Author: Adolf Ceska & Oldriska Ceska
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botanical illustration including Myriophyllum hippuroides

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Citation for this treatment: Adolf Ceska & Oldriska Ceska 2016. Myriophyllum hippuroides, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=34266, accessed on December 05, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on December 05, 2016.


Geographic subdivisions for Myriophyllum hippuroides:
NCoRO, NCoRI, n SNH, SnJV, n CCo, SnFrB;
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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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).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

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