The Triumph of Seeds (34 page)

The Millennium Seed Bank Partnership

Royal Botanic Gardens, Kew

Richmond, Surrey TW9 3AB, UK

Phone: +44 020 8332 5000

www.kew.org

Notes

P
REFACE
: “H
EED
!”

xv  
breadfruit seedlings overboard:
While the HMS
Bounty
gained fame for its mutiny, the purpose of the journey was botanical. At the suggestion of Sir Joseph Banks, president of the Royal Society, Captain Bligh’s orders involved the transport of live breadfruit trees from their native Tahiti to the West Indies, where plantation owners hoped they would yield cheap sustenance for the growing slave population. After his eventual return to England, Bligh set forth again in the HMS
Providence
and completed his original commission, delivering over 2,000 healthy saplings to Jamaica. Although the trees thrived in their new home, the scheme failed in light of one detail that had been overlooked: African slaves found Polynesian breadfruit disgusting and refused to eat it.

xvi  
addressed only briefly in these pages:
For insightful analyses on genetically modified crops, see Cummings 2008 and Hart 2002.

I
NTRODUCTION
: T
HE
F
IERCE
E
NERGY

xxii  
“just as the little boy had known it would”:
Krauss 1945.

xxii  
352,000 other kinds of plants that use seeds to reproduce:
Estimates of the number of seed plants vary from 200,000 to over 420,000 (Scotland and Wortley 2003). The figure used here comes from an ongoing collaboration among the world’s largest herbaria, including Kew Gardens, the New York Botanical
Garden, and the Missouri Botanical Garden (The Plant List 2013, Version 1.1, archived at
www.theplantlist.org
).

C
HAPTER
O
NE
: S
EED FOR A
D
AY

3  
length of its own body:
Herpetologists with high-speed cameras have repeatedly shown that viper strikes reach only about a third or a half of their body length (e.g., Kardong and Bels 1998). Even well-informed observers, however, often give wildly exaggerated accounts of snake strikes (see Klauber 1956 for great examples). Having seen a fer-de-lance (
Bothrops asper
) in action, I’ll throw my lot in with the hyperbolists—anything seems possible when those fangs are headed in your direction.

6  
rainforest in the first place:
A member of the pea family,
almendro
is known to science as
Dipteryx panamensis
(also
D. oleifera
). With apologies for the self-reference, see Hanson et al. 2006, 2007, and 2008 for more on the
almendro
’s role as a keystone species in Central American rainforests.

7  
rapidly developing rural landscape:
I also had an ulterior motive. Before my
almendro
study, I had worked on projects involving mountain gorillas and brown bears, species known in the trade as “charismatic megafauna,” the big fancy animals. In the
almendro
, the plant lover inside me saw a chance to promote “charismatic megaflora.” What better way to describe a 150-foot keystone tree with iron-hard wood and Marge Simpson’s haircut?

9  
rainforests of southern Mexico and Guatemala:
The avocado tree (
Persea americana
) is known only as a cultivated species. Sometime in the thousands of years since domestication, its wild ancestor disappeared from the forests of Central America. One theory suggests that many large-fruited neo-tropical trees faded away following the loss of their seed dispersers: giant armadillos, glyptodonts, mammoths, gomphotheres, and other extinct Pleistocene megafauna (Janzen and Martin 1982). With its massive seed, the wild avocado would certainly have required the services of a large-bodied animal to move it around. (Of course, people now play that role quite well, and avocados can be found growing on every continent except Antarctica!)

11  
always right for sprouting:
Botanists call seeds that don’t survive desiccation
recalcitrant
. Though rare in temperate and seasonal climates, this strategy is found in an estimated 70 percent
of tropical rainforest trees, where quick germination offers more of an advantage than long-term dormancy. What works in a jungle, however, makes things difficult in a storage facility. Christina Walters at the US National Seed Bank calls recalcitrant seeds “spoiled little children,” but has found some success flash-freezing isolated embryos in liquid nitrogen.

12  
tenth of an ounce I’ve ever measured:
Because they never dry out and enter a truly desiccated, dormant state, avocado seeds take up only a small amount of water, essentially participating only in the last stage of full imbibation. Dry seeds generally imbibe two to three times their weight in water.

14  
stifling effects of the caffeinated bean:
Cell division in plants takes place in specialized tissue called
meristem
, which is located primarily at the tips of growing roots and stems. Once the coffee’s expanding cells push these tips out and away from the caffeine, the meristem can divide, and growth through division begins—a tidy system.

15  
“. . . season at which each is sown”:
Theophrastus 1916.

17  
layers of the surrounding fruit:
The impenetrable shell of an
almendro
seed, for instance, consists primarily of
endocarp
, the innermost layer of the fruit.

17  
major divisions in the plant kingdom:
It speaks to the fundamental importance of seeds in plant evolution that they are used to define so many lineages:
gymnosperms
(the “naked seeds”);
angiosperms
(the flowering plants, or “enclosed seeds”);
monocots
(angiosperms with one cotyledon);
dicots
(angiosperms with two cotyledons). Even fine-scale relationships among species and closely related groups can often be made based on the structure of their seeds.

C
HAPTER
T
WO
: T
HE
S
TAFF OF
L
IFE

20  
grass pride in a grass place:
One of the unexpected results of this work was the rediscovery of the giant Palouse earthworm (
Driloleirus americanus
), a native species long thought to have gone extinct with the decline of the prairies. Though recent specimens are smaller, this albino night crawler is rumored to reach three feet in length and to smell distinctly of lilies!

22  
70 percent of the land in cultivation:
Traditionally, the word
cereal
described the edible seeds of annual grasses, while
grain
was a more general term that included the seeds of plants like buckwheat (in the same family as rhubarb) or quinoa (related to beets and spinach). As a result of the overwhelming success of the W. K. Kellogg and C. W. Post companies, however, cereal has now become inextricably linked with breakfast food, leaving grain as a catchall for grass and grass-like crops. It’s too bad, since cereal was more descriptive and took its root from the lovely Ceres, Roman goddess of agriculture.

22  
grass seeds still feed the world:
Technically, each “grain” of a grass is a tiny fruit called a
caryopsis
. The fruit layers have adapted to serve as a hardened seed coat, however, and are indistinguishable from the seed material even under magnification. In all but the strictest interpretations, the caryopsis can be considered a de facto seed.

23  
unoccupied real estate:
Grasses evolved during an arid period in the Early Eocene, with a suite of traits adapted to life on the open plains. They are wind-pollinated and grow from the base, low to the ground, which helps them recover quickly from grazing or wildfires. Their leaves even contain glass-like silica crystals designed to wear down the teeth of the bison, horses, and other herd animals that feed on them.

24  
successful strategy:
It’s also worth keeping in mind that while grass seeds appear small to us, they can be quite large compared to the size of the plant and do represent a considerable investment of energy, particularly for annuals.

25  
like a steel wire:
For a very enjoyable account of the chemistry behind this statement, see Chapter 4 in Le Couteur and Burreson’s book
Napoleon’s Buttons
(2003).

26  
“. . . the cooking ape”:
According to Wrangham, modern proponents of a raw-food diet survive only through the largess of well-stocked grocery stores, and even then show signs of nutritional stress. In a natural setting, where food resources are scattered and seasonal, people would starve without the substantial energetic boost that comes through cooking (see Wrangham 2009).

27  
fruit, nuts, and seeds:
In addition to cooking, mastery of fire gave ancient people the ability to gather honey by smoking bees from their nests. For a fascinating discussion of this development, and our coevolution with a bird called the Greater Honeyguide, see Wrangham 2011.

27  
provide an invaluable comparison:
For more information on the many anthropological and archaeological notes in this paragraph, see Clarke 2007; Reddy 2009; Cowan 1978; Piperno et al. 2004; Mercader 2009; and Goren-Inbar et al. 2004.

28  
before our species even evolved:
I am consciously using the inclusive
sensu lato
definition of
H. erectus
, though some authors prefer to split this species into an earlier African form (
H. ergaster
) and a later Asian form (
H. erectus
). Isotopic evidence, as well as teeth wear on fossils, suggest that grass in the diet stretches back much farther, to early hominins like
Australopithecus
. Lee-Thorp et al. (2012) believe they were eating the fibrous roots of wetland grasses and sedges year round, in which case it’s likely the more nutritious seeds would have been relished when in season.

28  
varieties of wheat, rye, and barley:
In addition to efficiency and convenience in planting, there is evidence that a sudden cool and dry climate shift helped push these early agriculturalists toward a few hearty varieties (Hillman et al. 2001).

28  
resources into seed production:
Advocates for sustainable agriculture have begun developing large-seeded perennial grasses as alternatives to annual grains. If successful, these crops offer considerable advantages in erosion control, carbon sequestration, and reduced dependence on fertilizers and herbicide (Glover et al. 2010).

29  
“. . . explaining the course of human history”:
For more on this statement, see Diamond 1999, 139, and Blumler 1998.

30  
“. . . destroyed the Western Empire”:
Fraser and Rimas 2010, 64.

30  
fur of the common black rat:
Symptoms of bubonic plague are brought on by
Yersinia pestis
, a bacteria passed among people and rats through flea bites. Though infected fleas also eventually succumb, they can survive for many weeks as the bacteria population builds up in their mid-gut.

35  
“. . . bored shitless”:
Harden 1996, 32.

35  
$4 billion in today’s currency:
For more information on the history of the Snake River dams, see Peterson and Reed 1994 and Harden 1996.

37  
both in flavor and nutrition:
“Complete” proteins contain usable amounts of nine amino acids that the body needs yet can’t produce itself. They must be obtained through diet. Most meat
and dairy proteins are complete, but many plant foods lack one or more of the essential amino acids.

C
HAPTER
T
HREE:
S
OMETIMES
Y
OU
F
EEL
L
IKE A
N
UT