TRIFOLIUM -
CLOVER
Author:Brenda Kay Rone
Class E-Mail Address:350rone@dial.pick.uga.edu
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T.pratense | T.repens |
Courtesy of UGA Herbarium | Courtesy of UGA Herbarium |
Table of Contents
brenda
Higher Taxon:
Family: Fabaceae
Description:
There are approximately 240 species in the genus Trifolium (Zohary and Heller, 1984). They describe the genus as follows, "...Annuals and perennials. Leaves 3-, rarely 5-9- foliolate. Flowers variously colored, small to medium sized, mostly arranged in heads or spike-like racemes, umbels or very rarely solitary. Bracts conspicuous to minute or 0; sometimes inflorescences involucrate by connate lower bracts. Pod oblong or obovoid, ususally enclosed within calyx but sometimes longer than calyx, 1-2-, rarely many-seeded, mostly indehiscent" (Zohary and Heller, 1984).
Species List:
This species list displays the scientific and common names for Trifolium. This is an incomplete list taken from the Clover Science and Technology by Gillet (1985). Detailed information is offered for the species T.pratense and T.repens.
Table I. Scientific and Common Names of Genus Trifolium
(Gillet, 1985)
Scientific Names |
Common Names |
T.alexandrinum |
. |
T.ambiguum |
. |
T.arvense |
Rabbit Foot Clover |
T.aureum |
. |
T.campestre |
Low Hop Clover |
T.dubium |
Low Hop Clover |
T.fragiferum |
. |
T.glomeratum |
. |
T.hirtum |
. |
T.hybrium |
. |
T.incarnatum |
Crimson Clover |
T.medium |
. |
T.nigrescens |
. |
T.pratense |
Red Clover |
T.repens |
White Clover |
T.resupinatum |
. |
T.striatum |
. |
.T.subterrranuem |
. |
T.tomentosum |
. |
T.vesiculosum |
. |
Identification Guide:
The following is an identification guide to determine the different species of Trifolium by their distinguishing characteristics. This key is taken from the section by Gillet in Clover Science and Technology. This key is only partial representation of the species in the genus Trifolium.
"A. Surface tuberculate
B. Radicle slightly longer than cotyledons;surface reddish brown to almost black
..............................................T.vesiculosum (sect. MISTYLLUS)
BB. Radicle about equal to cotyledons;surface yellow
..............................................T.glomeratum
(sect. MICRANTHEMUM)
AA. Surface smooth
C. Oblongoid, 2.6 X 3 mm long; dark reddish brown; hilum depressed below the surface
brown; hilum depressed below the surface, with a light ring around it.
...............................................T.subterraneum
(sect. TRICHOCEPHALUM)
CC. Smaller, less than 2.5 mm; or some other color
D. Radicle slightly longer than cotyledons (sect. VESICARIA)
E. Surface orange-yellow with or without greenish-brown flecks
F. 1.9 to 2.2 mm long, 1.5 to 1.6 mm wide; speckled
.............................................. T.fragiferum
FF. 1.1 to 1.3 mm long, 0.9 to 1.1 mm wide; clear yellow without speckles
............................................. T.tomentosum
EE. Surface clear olive-green
............................................. T.resupinatum
DD. Radicle equal to or shorter than cotyledons
G. Radicle divergent from cotyledons(not strikingly so in T.nigrescens
H. Radicle ca 0.75 x the cotyledons
I. Large, 1.8 to 2.2 mm long, 1.3 to 1.5 mm wide, appearing strikingly
angular and somewhat flattened; pale brown to reddish brown
............................................. T.ambiguum
II. Smaller, not over 1.3mm long and 1.1mm wide; somewhat flattened
but not strongly so; yellow to various brown shades
J. Dull; 1.1 to 1.3 mm long; reddish brown to light brown
...............................................T.repens
T.hybridum
(not further
distinguishable)
JJ. Shiny; 0.7 to 0.8 mm long, 0.6 to 0.7mm wide; yellow to pale brown
............................................... T.nigrescens
HH. Radicle ca 0.5 X the cotyledons
K. Flattened, often purple-tinged, pale brown stripe form hilum to cotyledon end, cotyledon truncate; seed angular
............................................... T.pratense
KK. More rounded,only slightly flattened, lemon yellow to pale brown, red- brown stripe from hilum to cotyledon end; cotyledon rounded at the end
...............................................T.medium
GG. Radicle closely appressed to cotyledons
L. Width not less than 1.1 mm; yellow brown or red markings
M. Smaller than 1.5 mm long
N. Yellow with few to many small red spots; radicle subequal to or slightly smaller than cotyledons
...............................................T.lappaceum
NN. Yellow to pale brown, without spots; radicle 0.75 X cotyledons, or less
..............................................T.striatum
MM. Longer than 1.6 mm long
O. Hilum and micropyle surrounded by a reddish brown area
P. Widest near the middle, somewhat oblongoid; shiny
...............................................T.incarnatum
PP. Widest below the middle, ovoid; very slightly shiny
...............................................T.alexandrinum
OO. Hilum and micropyle without distinct coloration
Q. Less than 1 mm long
................................................T.arvense
QQ. 2 mm or more long
................................................T.hirtum
LL. Width less than 1.1 mm; yellow or reddish brown.........(sect.
CHRONOSEMIUM)
R. Surface Yellow
.................................................T.campestre
RR. Surface brown
S. 0.7 to 0.8 mm wide; often greenish at basal end
..................................................T.aureum
SS. 0.9 to 1.1 mm wide; clear brown without green
..................................................T.dubium"
To view a closer picture of T.repens look at the page by TimeLife(http://wwwlpathfinder.com/@@13fyQUA@9oWvRfC/vg/TimeLife/CG/Books?e16/Heml?E16095X.html) and a site on Papilionaceae(http://www.laters.com/weeds/clover.htm). To view T.pratense from a distance look at the site by HALLoGRAM on herbs(http://www.1001herbs.com/redclover/).
General Information:
Many species of the genus Trifolium flourish in wide varieties of habitats ranging form sub-Arctic regions to tropical regions of Africa and South America (Zohary and Heller, 1984). Furthermore, "At least two-thirds of the species in this genus are limited to natural habitats; such as mountain peaks, rocky slopes, mountain forests, forest clearing, meadows, and alpine zones with elevations seven exceeding 4,000m"(Gillet, 1985). Trifolium is fertilized through pollination by insects such as the honeybees, bumblebees and Lepidoptera(Zohary and Heller, 1984). Clover plays an important role in pasture lands through its nourishment to animals and beneficiary acts to grass when winter kills and summer droughts occur(http://www.modernforage.com/clover.htm) . However, evidence has shown that some clovers can cause poisoning to livestock(http://res.agr.ca/cgi-bin/brd/poisonpl/ddp...5?plant=Trifolium+repens&info=all&name=sci) . In additon, some clovers have medicinal purposes in the areas of blood purification and relief from inflammation and coughing(http://www.1001herbs.com/redclover/).
References:
- Gillet, J.W. 1985.
Clover Science and Technology. American Society of Agronomy, Inc. Madison, WI
- Zohary, M. and D. Heller. 1984.
The Genus Trifolium. The Israel Academy of Sciences and Humanities. Jerusalem
- http://www.pathfinder.com/@@*13fyQUA@9oWvRfC/vg/TimeLife/CG/Books/E16/Html
- http://www.laters.com/weeds/clover.htm
- http://www.1001herbs.com/redclover/
- http://www.modernforage.com/clover.htm
- http://res.agr.ca/cgi-bin/brd/poisonpl/ddp...5?plant=Trifolium+repens&info=all&name=sci
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