Plants and People
Major Families II
Grains and Legumes
Why grains and legumes?
And why together?
Grain + legume = complete protein
That peanut butter sandwich is looking pretty good now, isn’t it?
Poaceae - The Grass Family
 Humans devote more than 70% of the Earth’s farmlands
to the production of cereal grains
 Grasses provide at least 50% of the world’s caloric
intake
 Some anthropologists are of the opinion that the use of
cereal grain was a prerequisite for the formation of a
civilization
Vegetative Characteristics
Grass Inflorescence
The spikelet is the basic unit of grass inflorescence, with one or more florets
making up the spikelet. The spikelet is subtended by two sterile bracts known as
glumes. The glumes define the spikelet: they and everything above them make
up the spikelet.
Spikelet
Floret
Glumes
Floral Morphology
Flowers of the grass family are highly reduced and non-showy and are described
using unique terminology.
• The perianth has been reduced to structures
colled lodicules, located at the base of the ovary
(these may be absent)
• The mature ovary (fruit) is termed a grain or
caryopsis
• Each flower is enclosed by two fertile bracts,
with the larger, lower bract, the lemma enclosing
the usually smaller, upper bract termed the palea
• The tip of a glume, lemma or palea may be
extended into a bristle-like structure called an awn
• The lemma, palea and the flower make up the
floret
Floral Morphology
An oat spikelet:
palea 1
palea 2
anthers
stigma
awn 1
lemma 1
lemma 2
awn 2
glumes
The Beans
Caesalpiniaceae/
Caesalpinoideae
Fabaceae/
Papilionoideae/
Faboideae
Legumes
Mimosaceae/
Mimosoideae
The Bean Families
• Everyone agrees that the legumes form a coherent whole
based on the presence of a single carpel that matures into a
legume.
•They can be divided into three groups based on the
arrangement and structure of the androecium and perianth,
collectively called the androperianth.
•The question is whether to :
--treat them all as a single family Fabaceae (broad sense) with
three subfamilies
or
--treat them as separate families in the order Fabales.
Fabaceae (strict sense),
Papilionoideae/Faboideae
Flowers in Fabaceae are zygomorphic and papilionaceous (butterflylike). The corolla is consists of 5 petals: a banner, 2 wings, and a
fused keel. The banner is exterior to the wings.
The fused keel encloses the unique androecium, 10 stamens in 9
fused+ 1 free arrangement (this is termed diadelphous.) The
stamens surround the style but are not fused to it.
Caesalpiniaceae/ Caesalpinioideae
Flowers in the Caesalpiniaceae Family are zygomorphic and papilionaceous
(butterfly-like). The corolla is consists of 5 petals: a banner, 2 wings, and 2
un-united keel petals. There are 10 stamens that are free and often unalike.
The banner is usually located interior to the wings.
banner
wings
keel petals
(not fused)
Mimosaceae/Mimosoideae
Flowers in the Mimosaceae are actinomorphic. Many tiny flowers, each
with long, showy stamens, are grouped into globose or elongated
inflorescences. These stamens are the showy part of the flower, rather than
petals. The corolla is either free or fused.
stamens
corolla
calyx
an individual flower
Pseudocereals
A pseudocereal is a plant that produces a grain-like fruit
That is not a true caryopsis.
Often, these plants are grown in areas that are too cold,
too dry, or too high to grow cereals successfully.
Quinoa
Chenopodium quinoa—Chenopodiaceae
Native to the Andes of South America.
Cultivated since about 3,000 B.C.
Tolerates high altitude, cold, drought. Does
well in parts of North America.
Amaranth
Various species of Amaranthus--Amaranthaceae.
Native to the Americas. Was a staple of the Aztecs.
Cultivated since ca. 6,000 BC.
High in lysine.
Buckwheat
Fagopyrum esculentum – Polygonaceae
Native to Southeast Asia. Domesticated
around 6,000 B.C.
Lab Today
• Make sure to examine the oat spikelet dissected for you under
one of the microscopes and the vegetative parts of a grass.
• Sketch your own diagram of the oat spikelet, labeling the
important terms, and make sure you understand the different
parts of the spiklet!
• Compare the sample legume material with information given
to you in lecture, paying close attention to the arrangement and
structure of the androecium and perianth.
• Examine the grains, legumes, and pseudo-cereals, filling out
the table provided for today’s lab