The Triumph of Seeds (37 page)

169  
working in labs around the world:
See Preedy et al. 2011.

171  
kill a full-grown cow:
This fact would not surprise mycologists like Noelle Machnicki one bit. Research continues to show that many botanical compounds are actually the product of plant-fungi interactions, and in some cases they are made entirely by fungi living on or within the plant.

C
HAPTER
T
WELVE
: I
RRESISTIBLE
F
LESH

180  
ever laying eyes on one:
The main long-distance disperser of
almendro
is the great fruit-eating bat (
Artibeus lituratus
). The Jamaican fruit-eating bat occasionally disperses the fruit as well, but other bat species are considered too small to carry a normal-sized
almendro
fruit (see Bonaccorso et al. 1980).

181  
helped me take the data further:
Another aspect of my research tracked the dispersal of pollen and found a similar result. Bees lured by
almendro
’s prolific purple flowers would fly nearly a mile and a half (2.3 kilometers) between trees, moving pollen among even the most isolated individuals.

184  
attract otherwise carnivorous ants:
Called
eliasomes
, these fatty, protein-rich blobs lie at the heart of ant-plant interactions. The strategy has evolved at least one hundred times in groups as distinct as sedges, violets, and acacia trees. While most ant-dispersal distances are short, seeds in at least one case have been carried nearly 600 feet (180 meters) (Whitney 2002).

185  
“. . . out of their minds”:
Cohen 1969, 132.

185  
(and as yet unknown) seed disperser:
Many botanists include
manzanillo
on the list of plants possibly dispersed by gomphotheres or some other long-extinct megafauna.

188  
common in gymnosperms:
While people associate fruits with the flowering plants, animal dispersal is actually far more widespread in the gymnosperms. It occurs in 64 percent of gymnosperm families, and only 27 percent of angiosperm families (see Herrera and Pellmyr 2002 and Tiffney 2004).

190  
particular types of dispersers:
Botanists call these strategies
dispersal syndromes
. But while they offer a useful way to categorize plant-animal interactions, their role in actually driving plant evolution remains controversial.

190  
fertilizing dung:
In some cases the dung pile is beneficial, but when it contains too many seeds that sprout all at once, the intense competition can counteract the benefits of the fertilizer.

C
HAPTER
T
HIRTEEN
: B
Y
W
IND AND
W
AVE

193  
“. . . Daisy from a Dandelion”:
From letter to J. D. Hooker, 1846 (van Wyhe 2002).

193  
“. . . no botanist”:
Letter from J. S. Henslow to W. J. Hooker, 1836, as cited in Porter 1980.

194  
“Brazil without big trees”:
from Darwin’s Galapagos Notebook (van Wyhe 2002).

194  
“. . . arctic, than an equatorial Flora”:
Darwin 1871, 374.

195  
“. . . their nature but nothing else”:
Columbus 1990, 97.

195  
“. . . fields like roses”:
Cohen 1969, 79.

197  
idea took hold:
Mandeville’s original text describes the gourd lambs as “without wool” and suggests they were grown for the table rather than the loom. He even claims to have tasted one, proclaiming the flavor “wonderful.” Recent interpretations often omit this text, however. The Mandeville quotation about cotton trees with “pliable branches” and “hungrie” lambs appears to be a complete fabrication, spread in part by its inclusion in his Wikipedia entry.

200  
375 feet (120 meters):
Dauer et al. 2009.

200  
prey upon the springtails:
See Swan 1992 for a fascinating description of this wind-dependent high-altitude ecosystem, which he calls “the Aeolian biome.”

200  
300 miles (483 kilometers) on an average Atlantic current:
Darwin later upped that estimate to 924 miles (1,487 kilometers) when he realized that whole, dried plants stayed afloat much longer.

201  
“. . . coming to maturity!”:
Darwin 1859, 228.

201  
archipelago by similar means:
Porter (1984) attributed 134 colonizations to wind and 36 to drift, allowing that some, like cotton, were a combination of both.

201  
“a miracle squared”:
de Queiroz 2014, 287.

202  
“the revolutionary fiber,” and “the fuel of the industrial revolution”:
Yafa 2005, 70; Riello 2013, 2.

202  
“. . . you have no modern industry”:
McLellan 2000, 221.

203  
Europe’s growing middle class:
Simply reading the tags at a modern fabric store quickly reveals the roles of Asia and the Near East in the history of cotton. In addition to calicos from Calicut, one finds madras (from the city of Madras), chintzes (from the Hindi word for “paint” or “splatter”), khakis (from the Urdu for “dust-colored”), gingham (from the Malay word for “striped”), and seersucker (from the Persian for “milk and sugar,” a reference to the bunched and smooth pattern of the fabric).

204  
its African and Asian relations:
The long-fibered New World cottons resulted from hybridization between two Old World varieties. They are what geneticists call
tetraploids
, with double the normal number of chromosomes. Of the five recognized species, upland cotton (
G. hirsutum
) now dominates the world market. Sea Island cotton (
G. barbadense
) has the longest fibers, but it is harder to grow. It persists in the marketplace for high-end fabrics, usually under the trade names “Egyptian Cotton” or “Peruvian Pima.”

205  
Middle Passage to America every year:
See Klein 2002.

207  
twice that rate:
The winged samaras of a maple may fall faster than a Javan cucumber seed, but they have inspired aircraft of their own. Lockheed Martin manufactures the “Samarai,” a surveillance drone that gyrates like a maple, and Australian researchers recently unveiled a disposable whirligig designed to transmit atmospheric conditions from the air above a forest fire. Single-rotor helicopters have also been built, but they generally lack the stability necessary for manned flight.

210  
laughed until it disappeared from view:
Watching that Javan cucumber seed fly was a thrill, but I also felt a certain unease as it drifted out of sight. What if it sprouted? Though it’s extremely unlikely that a tropical vine would thrive in our cool climate, I couldn’t help wondering whether Noah and I had just introduced the future kudzu of the Pacific Northwest!

C
ONCLUSION
: T
HE
F
UTURE OF
S
EEDS

212  
doubled chemically:
The chemical in question is
colchicine
, an alkaloid found in the seeds and tubers of the autumn crocus.

Glossary

acellular endosperm
  An unusual substance found in coconuts, known in the grocery store as “coconut water.” It consists of free nuclei floating in a nutritious cytoplasmic bath. As the coconut matures, cell walls form, and much of this material transforms into the meat (i.e., solid endosperm) of the coconut. (Some other seed endosperms pass through a brief acellular stage very early in their development, but only coconuts maintain it for so long and in such quantities.)

adenosine
  A compound with a wide range of vital functions in biochemistry. In the brain, it plays an important role in signaling fatigue and guiding the body toward sleep.

alkaloid
  Any of a large group of nitrogen-based compounds produced by plants and some marine organisms. They often function as chemical defenses, and many of them, including stimulants (e.g., caffeine), drugs (e.g., morphine), and poisons (e.g., strychnine), produce a strong reaction in people.

allele
  One of the possible forms of a gene, determined by differences in DNA and resulting in different expressions of that gene (e.g., wrinkled vs. smooth peas, or brown vs. red hair in people).

angiosperm
  A “flowering plant,” defined by having its seed enclosed in tissue to form a carpel (see
carpel
, below). The vast majority of living plants are angiosperms.

apomixis
  Asexual reproduction in plants that occurs when egg cells are produced with a full set of chromosomes, requiring no fertilization by pollen. The resulting seeds are essentially clone-like offspring of the parent. This strategy has evolved occasionally in a wide range of plant families, but is perhaps most common in the
asters, including the dandelion, and the hawkweeds that so confounded Gregor Mendel.

caffeine
  An alkaloid found in a number of plants (notably coffee, tea, kola, and cacao) that helps deter attacks by insects and other pests, and may also function in the soil as an herbicide and germination inhibitor. Used by people as a stimulant.

carbohydrate
  A group of compounds in biochemistry composed of carbon, hydrogen, and oxygen atoms in various combinations. The results are generically called
sugars
, but they can be used for everything from energy storage in seeds (e.g., starch) to the exoskeleton of insects (called
chitin
).

Carboniferous
  The fifth Period of the Paleozoic Era, following the Devonian and lasting from 360 million to 286 million years ago (includes the Mississippian and Pennsylvanian sub-periods).

carpel
  The defining characteristic of the angiosperms that evolved from the leaves or bracts that surrounded and enclosed the seed, forming a protective layer and spurring a host of new adaptations for defense, pollination, and dispersal. One or more carpels make up what is considered the female portion of a typical angiosperm flower, including the ovary, stigma, and style.

caryopsis
  A type of fruit generally understood as the “seeds” of grasses.

cereal
  An annual, grain-bearing grass (e.g., wheat, barley, rye, oats, corn, rice).

chromosome
  The structure that bears the genetic information of a plant or animal. Chromosomes consist of the double-helix DNA molecule and surrounding proteins and serve as bulk units of inheritance between generations. In sexual reproduction, individuals receive half their chromosomes from each parent.

coevolution
  Process of evolution where changes in one organism spur changes in another. Traditionally, coevolution has been defined as a reciprocal interaction between two species, but it is now understood to be far more nuanced, producing changes within networks of interacting species that can vary across geography and through time.

copra
  The “meat” of a coconut, formed from solid, cellular endosperm.

cotyledon
  The embryonic leaf of a baby plant, also called a “seed leaf.” Cotyledons are well known to gardeners as the first leaves of germinating seedlings, and are also familiar when they are particularly large and tasty within the seed itself (e.g., the two halves of a peanut).

Cretaceous
  The final period of the Mesozoic Era, following the Jurassic and lasting from 146 million to 65 million years ago.

cytotoxin
  A poison that physically kills individual cells, as opposed to a neurotoxin, which causes paralysis or other damage to the nervous system.

dicot
  A major group of flowering plants defined by the presence of two cotyledons (
di-cot
) in the seed.

diploid
  The condition of having two sets of chromosomes, one from each parent.

dormancy
  Generally understood as the period of inactivity between the maturation of a seed and its germination. Technically, true dormancy applies only to those seeds that actively resist germination until various physical or chemical requirements are met (e.g., changes in light, temperature, and moisture, or exposure to wood smoke).

electron micrograph
  An image taken at extreme magnification by an electron microscope.

eliasome
  A rich, fatty packet attached to a seed to encourage seed dispersal by ants.

embryo
  In general, an unborn offspring. In botany, this term refers to the baby plant found within a seed.