Plantain
Family - Plantaginaceae
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Plantain Family - Alismataceae |
Greater
Plantain (Plantago
major)
has broad oval to elliptical leaves narrowed into
long stalks (as long as the leaf blades). The inflorescence is about as long as the
leaves (10-15 cm, 4 - 6 inches).
long stalks (as long as the leaf blades). The inflorescence is about as long as the
leaves (10-15 cm, 4 - 6 inches).
Ribwort
(Plantago
lanceolata)
has narrower (lanceolate)
leaves than Plantago major and shorter flower spikes.
The flower spikes are also a darker colour. Although
thought to be wind-pollinated it has recently been
observed that honeybees frequent the flowers.
leaves than Plantago major and shorter flower spikes.
The flower spikes are also a darker colour. Although
thought to be wind-pollinated it has recently been
observed that honeybees frequent the flowers.
The tall
inflorescence springs from a rosette of leaves and bears many
flowers clustered together in a spike.
The flowers develop first at the base of the spike and the female parts mature before the male parts
(protogyny). The whorl of white hairlike tufts seen protruding in the specimen above are the anthers of the
mature male flowers. This separation in time, between the development of the female and male organs helps
promote cross-pollination. Even though plantains may exhibit genetic self-incompatibility (meaning that its
own pollen grains will not germinate when in contact with the female stigmas of the same plant, protogyny
reduces pollen-pistil interference which occurs when the plant's own (incompatible) pollen clogs the stigmas,
reducing the likelihood that pollen from another plant will attach. (The pistil is the female part of the flower,
comprising one or more carpels that may be fused together). Plantains are monocotyledons and mostly
wind-pollinated.
The flowers develop first at the base of the spike and the female parts mature before the male parts
(protogyny). The whorl of white hairlike tufts seen protruding in the specimen above are the anthers of the
mature male flowers. This separation in time, between the development of the female and male organs helps
promote cross-pollination. Even though plantains may exhibit genetic self-incompatibility (meaning that its
own pollen grains will not germinate when in contact with the female stigmas of the same plant, protogyny
reduces pollen-pistil interference which occurs when the plant's own (incompatible) pollen clogs the stigmas,
reducing the likelihood that pollen from another plant will attach. (The pistil is the female part of the flower,
comprising one or more carpels that may be fused together). Plantains are monocotyledons and mostly
wind-pollinated.
Above,
the fruit of the water plantain, Alisma
plantago-aquatica.
This plant was so-named
because of the resemblance of its leaves to those of Plantago, but actually belongs to a totally
different family of monocots. It grows in mud by ponds and slow-moving rivers. The flowers are
borne on pyramidal inflorescences, each at the end of a long stalk and each flower is up to 1 cm
across and has three lilac to white petals. Another species occurs in the same habitat: Alisma
lanceolatum, which has narrower (more lanceolate) leaves with less rounded, more tapered
(cuneate) leaf bases. However, leaf shape is highly variable and overlaps between the two
species, such that the only reliable form of classification is to look at the carpels or fruit
(achenes). In Alisma plantago-aquatica the single style is at the top of the ovary, but off to one
side. It maintains this lateral position as the ovary expands and develops into the achene. In
Alisma lanceolatum, the style begins at the apex of the ovary, in a much more central position.
However, as the achene develops it swells over and the top over-arches the style which gets
displaced more laterally. In mature A. lanceolatum the style may be anchored slightly more
towards the apex of the achene, but there is considerable variation. For definite identification the
young carpels have to be examined, with several being examined from each plant.
because of the resemblance of its leaves to those of Plantago, but actually belongs to a totally
different family of monocots. It grows in mud by ponds and slow-moving rivers. The flowers are
borne on pyramidal inflorescences, each at the end of a long stalk and each flower is up to 1 cm
across and has three lilac to white petals. Another species occurs in the same habitat: Alisma
lanceolatum, which has narrower (more lanceolate) leaves with less rounded, more tapered
(cuneate) leaf bases. However, leaf shape is highly variable and overlaps between the two
species, such that the only reliable form of classification is to look at the carpels or fruit
(achenes). In Alisma plantago-aquatica the single style is at the top of the ovary, but off to one
side. It maintains this lateral position as the ovary expands and develops into the achene. In
Alisma lanceolatum, the style begins at the apex of the ovary, in a much more central position.
However, as the achene develops it swells over and the top over-arches the style which gets
displaced more laterally. In mature A. lanceolatum the style may be anchored slightly more
towards the apex of the achene, but there is considerable variation. For definite identification the
young carpels have to be examined, with several being examined from each plant.
Above
and below: achenes from Alisma
plantago-aquatica,
showing the remains of the style
attached laterally. Mature achenes of Alisma lanceolatum may be similar, though there is a
tendency for the style to be slightly more towards the top (more apical) though this depends on
maturity. In Alisma plantago-aquatica a more distinctive keel may reveal the more lateral original
position of the style in the achene.
attached laterally. Mature achenes of Alisma lanceolatum may be similar, though there is a
tendency for the style to be slightly more towards the top (more apical) though this depends on
maturity. In Alisma plantago-aquatica a more distinctive keel may reveal the more lateral original
position of the style in the achene.
Above:
the differences in the developing carpels becomes readily
apparent. A: Alisma
plantago-aquatica, immature carpel; B: Alisma plantago-aquatica, carpel beginning to
develop; C: Alisma lanceolatum, immature carpel.
plantago-aquatica, immature carpel; B: Alisma plantago-aquatica, carpel beginning to
develop; C: Alisma lanceolatum, immature carpel.
To
further complicate taxonomy a hybrid form between A. plantago-aquatica and A.
lanceolatum, called Alisma x rhicnocarpum. The leaf shape is intermediate in these
forms and so more like a rectangle with rounded corners in contour. However, this is
perhaps more easily identified by the fact that it is almost entirely sterile with only one or
two achenes developing in each flower (are these sterile?). It will thus usually be found
in the vicinity of both parents.
lanceolatum, called Alisma x rhicnocarpum. The leaf shape is intermediate in these
forms and so more like a rectangle with rounded corners in contour. However, this is
perhaps more easily identified by the fact that it is almost entirely sterile with only one or
two achenes developing in each flower (are these sterile?). It will thus usually be found
in the vicinity of both parents.
Note the
lateral positions of the style remains.
Article
updated:
11/4/2015
9 Sep 2018
17 Sep 2018
29 Sep 2018
11/4/2015
9 Sep 2018
17 Sep 2018
29 Sep 2018
Hoary
Plantain (Plantago
media)
has a basal rosette of elliptical
to diamond-shaped leaves with 5 to 9 prominent veins and
short stalks. The inflorescence stalk is unfurrowed and the
white flowers have pinkish stamens with purple filaments.
Unusually for plantains the Hoary Plantain is insect-pollinated.
Found on calcareous grassland.
to diamond-shaped leaves with 5 to 9 prominent veins and
short stalks. The inflorescence stalk is unfurrowed and the
white flowers have pinkish stamens with purple filaments.
Unusually for plantains the Hoary Plantain is insect-pollinated.
Found on calcareous grassland.
Hoary Plantain Above
and below: Buck's-horn Plantain (Plantago
coronopus)
growing on a sea-wall. The
brownish flowers have yellow stamens. The leaves are pinnatifid (deeply divided) and form a
basal rosette.
brownish flowers have yellow stamens. The leaves are pinnatifid (deeply divided) and form a
basal rosette.
Above:
Water Plantain (Alisma plantago-aquatica). Photo by Jasenka Topic,
courtesy of:
http://www.freenatureimages.eu.
http://www.freenatureimages.eu.
Plantago
major
