Welcome back to another episode of LITFM, normally there would be a longer intro but the topic being tackled covers a detailed subject with examples and space is tight so, enjoy this look into biological diversity.
Today’s topic of discussion is the basic concept of
biological diversity. The reasoning to
speak about this here comes from a number of conversations at the farmer’s
market booth over the summer. I hear a lot of folks saying something like ‘there’s
more than one type of…” which amazes me. When you think about it the
aforementioned is a surprising statement because at the supermarket there are
many types of produce often side by side to match personal preferences. This
sort of thing makes me wonder why it’s so surprising to some out there that
there are differing types of plants otherwise. Case in point, one of our most
common medicinal plants Aloe barbadensis
or Aloe Vera is well known but other varieties in the family are relative
unknowns.
So let’s start with the biology of our example plant and
address the idea of biological diversity. Now the aloe is a good example of a
species that is well adapted to its climate which is for the most part arid
regions of Africa. This of course means that the Aloes have several critical
survival features for the climate. If you ever were to dig up a aloe and remove
all the soil you would see a rather good portrait of a traditional arid climate
succulent plant. The main feature below the surface is the thick primary root
which is more or less a tap root that has evolved to push through dry desert
soil to find moisture. If the Aloe you’re looking at was pot bound you might
see a number of thick roots all of which were geared towards finding moisture
and nutrient despite what the arid climate’s soil conditions might be. Above
ground you would see the central growing point or the crown, and a number of
alternating pattern triangular leaves each more of then then not swollen with
fluids. Those fluids in the leaves includes a slimy mucilage that acts as a
counter for water loss due to damage and as a predatory deterrent. If you can imagine having a mouth full of
something slippery and terrible tasting like dish soap you sort of get the
idea. It’s not pleasant and while more complex animals might have means to
handle this, in most cases insect pests are undone by it. This feature in turn
ensures the species survival, despite being a biological oddity to us and
indeed part of the plants medicinal allure.
All of this is an adaptation to handle the specific climate
in which the aloe grows specifically arid places where soil quality and moisture
are at a premium. The aloe itself reproduces in two ways, by flower and by
producing clones of itself. The first part about flowers is pretty standard;
the aloe will eventually bear a group of tube shaped flowers in a long stalk.
If pollenated these flowers will produce some form of fruiting body which then disperses
the offspring of the plant. Alternately aloe is also able to clone itself by producing
vegetative structures called offsets or ‘pups’. Thes mini aloes are connected
to the mother plant by little underground stems and generally serve to expend
the area the central plant occupies while also acting as a very efficient means
to out-compete competition. But this is not all; these offsets if separated from
the mother plant say by the mother plant being eaten; will continue on and as
noted prior be exact genetic copies of the mother. Some variation on this
asexual reproductive aspect is seen across the entire cactus and succulent
spectrum. For instance stressed rhipsalis and Christmas cacti will often ‘shatter’
and shed their fleshy pads or branches as a means to get the branches to
hopefully land in another pocket of soil thus keeping the species alive.
Likewise the Prickly pear under certain conditions will shed its fleshy pads to
perform the same action. The massive Sanguaro cactus will occasionally shed its
‘arms’ to do the same with odd results.
So these succulents are biologically set to survive and do so just fine
without our intervention.
This leads to a question, how much diversity could there be
in one given family if the core stuff is rather efficient already? Well you
would be surprised, as with song birds and their amazing variety of colored
plumage, plants are equally adapted to their specific niche and thus numerous
varieties exist. So lets take a look at what variety is out there in the aloe
family.
 |
| Aloe barbadensis - Aloe Vera |
Your typical medicinal aloe much like a head of cabbage is
the poster child for the family because we know it so well. To the point that
the natural populations of it may not exist anymore. This is the sad part of
the Aloe family’s story, it’s most known member is grown exclusively in
cultivation as no known natural stands of Aloe Vera are known to exist. On the
other hand in cultivation aloe has gone farther than would otherwise be
possible and to climates far beyond the native range of the originating plant.
 |
| Aloe ciliaris – Climbing Aloe |
Climbing aloe is an example of an regional adaptation.
Unlike Aloe Vera climbing aloe grows less in arid places but within the
thickets of the Eastern Cape of Africa. In order to climb this aloe has
developed leaves that are hook like in shape allowing it to rapidly use other
plants as support to get to the top of the thorny thickets it grows in. Furthermore
it is noted as being the fastest growing aloe which is another adaptation to
ensure its survival in a densely competitive environment.
 |
| Aloe deltoideodonta – Stemless Aloe |
It’s hard to say why stem less aloe is how it is but the
shortened stems could be a surface area reduction adaptation for an exceedingly
hot climate. Less stem means less hight means less area exposed to transpiration.
The odd checker board pattern on the leaves could be a form of mimicry designed
to break up the plant’s shape as it might look a bit like gravel or coarse sand
at a glance.
 |
| Aloe dorotheae – Sunset Aloe |
Sunset aloe is critically endangered in its native habitat
of Tanzania due to over collecting. Like Aloe Vera it is preferred for its
medicinal qualities but unlike Aloe Vera it is a slow grower no doubt due to its
genetics having not been selected for vigor or that it’s environment does not
encourage rapid growth It does display the odd trait of turning bright
orange-red in response to long-term exposure to bright sunlight. This
adaptation is seen in most aloes as a chemical-pigment defense against the sun’s
light scorching the plants. In the case of sunset aloe the defense is to an
extreme that makes it quite attractive. It may be that cultivation will
preserve this plant from complete extinction.
 |
| Aloe nobilis x A humilis – Crosby’s Prolific Aloe |
Crosby’s prolific is a man-made cross between two species of
aloe golden tooth aloe and spider aloe to make a cross that resembles true Aloe
Vera in that it has fat leaves but the limited leaf length seems to suggest
otherwise. Time will tell if it’s crossing to produce a new plant yields any
medical uses but the possibility that this plant is an aggressive grower could
be useful
 |
Aloe quicksilver x 'Rare Flare' - Silver Ridge Aloe
|
Silver Ridge Aloe is one of the few completely ornamental aloes out
there. Each leaf has a number of warty bits on it that act in function to toughen
the epidermis of the leaf. The side effect is that the leaves are rather flat
and there is little available gel. On one hand this plant is hard to predate
but on the other it’s probably tougher then leather. Either way its an interesting
cross.
 |
| Aloe variegata – Partridge Breast Aloe |
Partridge breast aloe is another example of a primarily ornamental
aloe because of its thin leaves which yield far less gel then the more
succulent varieties. Found naturally in the arid or semi-arid regions of South
Africa the partridge-breast or Tiger aloe has been in cultivation for some time.
Its adaptation seems to be a form of natural camouflage in the form of its
color and the shape of its leaves being a reasonable counter to moisture loss
due to the shape and angle of the leaves. Another unrelated plant, the Snake
Plant Sanseveria trifaciata uses the
same strategy of banded leaves with a v-shaped cross section
With all that said you can see that there is some clear
variation in just one family of plants, which means that of course if you keep
your eyes open you should be prepared to see some cool stuff. The objective of this article was to demonstrate the potential variety out there. Now this is a handful of examples compared to the vast ocean of species int he trade but hopefully it illustrates the variability of a species. Hopefully you now understand that, what you see most often may not be entirely the case with whats out there. Some say we need to go to space to discover, but indeed personal discovery can be had at your local nursery or plant supplier. But speaking of local plant suppliers you can
find the BL2/LITFM table teamed up with the Sustainable Neighbors every
Saturday, between 9am and 1pm at the Fayetteville City/Farmer’s market. The
market is located at 325 Franklin Street which is the street address of the
Fayetteville Transportation museum. The market is located in the Museum’s parking
lot and the area is surrounded by free or reduced cost parking.
The Stuff that’s on sale: (last week for this stuff folks!)
4x Pepper, Habenero (Spicy)
1x Pepper, Yellow Banana
1x Pepper, Sweet Ghost
2x Herb, Horehound
House Plants:
2x Medicinal Aloe
1x Dancing Bones Cactus
4x Silver Ridge Aloe
2x Desert Rose
Perennials:
2x Coneflower, Magnus
Vegetables:
6x Cabbage-Collards, Morris Heading
1x Onion, Egyptian
-I’ll probably toss a few extras on the truck this week so
check the table if you can!-
Coming Next Week:
20x Collards, Morris Heading Type
15x Asian Cabbage, Napa Type
12x Lettuce, Salad Bowl
20x Kale, Lacinato/Black Cabbage/ Dinosaur
Coming Soon:
6x Asian Cabbage, Senposai
10x Mustard, India
??x Mustard, Japanese Red Giant (Spicier then normal R.G.)
??x Mustard, Red Giant
With that said this brings to a close another episode of
LITFM, feel free to hit up the booth for more info or a copy of Southward Skies
while you’re at the market. As always if you have a garden question I’m ready
to answer it so go ahead and as either here or in person! As always folks keep ‘em
growing!
