Transcript Sundews (aka Drosera)

Sundews
(a.k.a Drosera)
Habitat
•
Sundews generally grow in
seasonally moist or more rarely
constantly wet habitats with acidic
soils and high levels of sunlight.
Common habitats
include bogs, fens, swamps,
marshes, the tepuiss of Venezuela,
the wallums of coastal Australia,
the Fynbos of South Africa, and
moist streambanks. Many species
grow in association with sphagnum
moss, which absorbs much of the
soil's nutrient supply and also
acidifies the soil, making nutrients
less available to plant life. This
allows sundews, which don't rely on
soil-bound nutrients, to flourish
where more dominating vegetation
would usually outcompete them.
How Does A Sundew
Catch it’s Prey?
• Sundews have leaves which are covered in long hairs and
each hair ends in a droplet of sticky fluid which causes
insects to stick to the leaf.
The leaf, whatever shape, is covered in tiny hairs on the
dorsal side. Each of these hairs ends in a tiny, bulbous
gland. These glands secrete a viscous mucilage that
contains sweet smelling sugar, which acts as a lure.
When prey discovers the lure, they fly (or less often,
crawl) onto the leaf, becoming ensnared in the liquid.
Often, ground dwelling insects have legs powerful
enough to escape, but flying insects are not built strong
enough. Their wings may become ensnared as well.
Limbs may be torn off in the struggle, etc. The mucilage
enters the insects breathing holes and suffocates it,
killing it. During the struggle, the tentacles curl around
toward the center of the leaf, through a complex water
pressure system inside the tentacles, impeding the preys
escape. In some species, this water pressure system is
included in the entire leaf, so the leaf may start to curl as
well.
Roots of Sundews
• The root system of most Drosera is only
weakly developed. It serves mainly to
absorb water and to anchor the plant to
the ground; the roots are relatively useless
when it comes to nutrient uptake. A few
South African species use their roots for
water and food storage. Some species
have wiry root systems that remain during
frosts if the stem dies. Some Australian
species form underground corms for this
purpose, which also serve to allow the
plants to survive dry summers.
Different Types of
Sundews
Pitcher Plant
By:
Minahil Masroor
Introduction:
• Pitcher plants are carnivorous plants whose preytrapping mechanism features a deep cavity filled
with liquid known as a pitfall trap. It has been
widely assumed that the various sorts of pitfall trap
evolved from rolled leaves, with selection pressure
favouring more deeply cupped leaves
over evolutionary time. However, some pitcher
plant genera (such as Nepenthes) are placed
withinclades consisting mostly of flypaper traps:
this indicates that this view may be too simplistic,
and some pitchers may have evolved from the
common ancestors of today's flypaper traps by loss
of mucilage.
• Types of pitcher plants:
•
•
The families Nepenthaceae and Sarraceniaceae are the best-known and
largest groups of pitcher plants.
The Nepenthaceae contains a single genus, Nepenthes, containing about
130 species and numerous hybrids and cultivars. In these Old World pitcher
plants, the pitchers are borne at the end of tendrils that extend from
the midrib of an otherwise unexceptional leaf. The plants themselves are
often climbers, accessing the canopy of their habitats using the
aforementioned tendrils, although others are found on the ground in forest
clearings, or as epiphytes on trees.
Distribution :
•
In contrast, the New World pitcher plants (Sarraceniaceae),
which comprise three genera, are ground-dwelling herbs whose
pitchers arise from a horizontal rhizome. In this family, the entire
leaf forms the pitcher, whereas in the Nepenthaceae, the pitcher
arises from the terminal portion of the leaf. The species
of Heliamphora, which are popularly known as marsh pitchers
(or erroneously as sun pitchers), have a simple rolled-leaf
pitcher, at the tip of which is a spoon-like structure that
secretes nectar. They are restricted to areas of high rainfall
in South America. TheNorth American genus Sarracenia are the
trumpet pitchers, which have a more complex trap
than Heliamphora, with an operculum, which prevents excess
accumulation of rainwater in most of the species. The single
species in the Californian genus Darlingtonia is popularly known
as the cobra plant, due to its possession of an inflated "lid" with
elegant false-exits, and a forked "tongue", which serves to ferry
ants and other prey to the entrance of the pitcher. The species
in the genus Sarracenia readily hybridise, making their
classification a complex matter.
Bibliography
Sundews:
1. Images were taken from Google.com
2. Information was taken from wikipedia.com
Pitcher Plant :
1. Wikipedia
2 .google
3 .Darwin Online
Butterwort:
1.Google
2. wikipedia