View of a Hybrid Stonecrop
Sedum x hybrida
by Brian Johnston (Canada)
stone-crop suffered to take root
window’s edge, profusely grew,
Characteristics such as attractive
appearance, and considerable hardiness, make members of the Sedum genus
popular landscaping plants. The common name Stonecrop is from
Middle English, and literally means “sprouting from the stone”.
This refers to the fact that the plant prefers good drainage, and is
therefore found growing amongst stones in the wild. The genus
name Sedum is from the Latin
sedere, which translates to ‘sit’, another reference to the plants
‘sitting’ on stones. Other experts believe that the ‘sit’ refers
to their low spreading habit, while still others translate ‘sedere’ as ‘to quiet’ and refer to
the plants’ supposed sedative properties!
Sedums are members of the Crassulaceae family, where this
name is derived from the Latin root word for ‘thick’ or ‘dense’.
This refers to the fact that its members are succulents which possess
water-storing leaves. It is these leaves that provide much of a
Stonecrop’s visual appeal, since its many flowers are relatively small.
The particular Stonecrop hybrid
studied in this article, Sedum ‘Sunkissed’, was about 50 centimetres in
height, and possessed white flowers with contrasting red anthers.
As you can see from the images that follow, the flowers do not provide
an initial visual impact.
On the other hand, even from a
distance, its unusually shaped thick leaves, positioned in spiral
fashion around the stem, may prompt a second look.
The leaves grow directly from the
stem with no stalk, and are thus referred to as clasping. Both
its major vein, and its serrated edge are tinged with red, adding to
the visual appeal.
Leaves form an acute angle with the
stem. Secondary veining exists, but it is certainly not prominent.
Closer views reveal that a leaf’s
upper surface has randomly positioned tiny red spots.
When leaves die and fall from the
stem, they leave behind distinctive scars.
Strangely, the stalk that supports
a new bud-stage flower-head grows from the point of connection of a
leaf to the stem (the leaf axil).
New buds have a pentagonal shape
when viewed from above. Notice an opening bud in each image.
The four images that follow show a
blooming flower-head. Only the red anthers provide any real
Each flower has five petals, and
its centre is filled with five pie-shaped, light green ovaries.
Careful examination of the three
images that follow reveals that some of a flower’s anthers are red, and
approximately oval in colour, while others are yellowish brown, and
more irregular in shape.
The larger red anthers are not yet
releasing their pollen. It appears as though they are covered by
protective membranes that eventually disintegrate to reveal the pollen
One of these colourful membranes
can be seen in the two photomicrographs below.
Each of the anther’s lobes appears
to split longitudinally in order to expose its pollen – a process
referred to as dehiscing.
Photomicrographs showing an
intermediate stage in this process can be seen below.
Stonecrop pollen grains appear
roughly ellipsoidal in shape.
There are few interesting details
at the tips of the flower’s pistils.
Even under the microscope, the
usual hair-like protuberances present on the receptive upper surface of
the stigma, are missing.
If one of a flower’s ovaries is
split open in order to reveal its contents, the developing seeds can be
The ridged outer surface of the
ovary can be seen in the photomicrograph below.
While photographing the flowers of
this plant, I noticed considerable activity on the surface of
anthers. Closer inspection revealed that the pollen seemed to be
the food of this extremely small insect. Whether there to feed on
pollen grains, or to suck fluid from the anther itself, this little
creature became coated in the pollen grains as it moved from anther to
There are approximately 600 species
of Stonecrop, most of them growing in the Northern Temperate
Zone. Based on the number of Stonecrop plants in my neighbours
gardens, they certainly are popular!
The low magnification, (to 1:1),
macro-photographs were taken using a 13 megapixel Canon 5D full frame
DSLR, using a Canon EF 180 mm 1:3.5 L Macro lens.
An 10 megapixel Canon 40D DSLR,
equipped with a specialized high magnification (1x to 5x) Canon macro
lens, the MP-E 65 mm 1:2.8, was used to take the remainder of the
The photomicrographs were taken
using a Leitz SM-Pol microscope (using a dark ground condenser), and
the Coolpix 4500.
A Flower Garden of
A complete graphical index of all
of my flower articles can be found here.
The Colourful World of
A complete graphical index of all
of my crystal articles can be found here.
Microscopy UK or their contributors.
Published in the July
2011 edition of Micscape.
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