Poaceae	01	Floral formula	01-Floral formula	The flowers of Poaceae are small, lack petals, and are pollinated by wind. The 2 sepals are modified into <B>lodicules.</B> There are 3 stamens that hang down and the anthers shed pollen into the wind. The syncarpous gynoecium has 2 carpels, the ovary is superior, the styles are feather-like to catch pollen from the wind, and the ovary is 1-locular with 1 basal ovule.	
Poaceae	02	Introduction	02-Introduction	The Poaceae is a very large family, and it is distributed just about worldwide. 	
Poaceae	03	Grains	03-Grains	 This is by far the most economically important plant family, especially for food as most "cereal" crops belong to the Poaceae.	
Poaceae	04	3 Grains	04-Grains	More than half of the basic nutrition for humans comes from the Poaceae, and especially rice, wheat, and corn.		
Poaceae	05	Grass vista	05-Grass vista	Grasses are also important in landscape plantings, such as this wonderful vista looking towards Windsor Castle in England.	
Poaceae	06	Football turm	06-Football turf	Grasses are also of great importance in many athletic games, such as football, baseball, golf, and soccer.	
Poaceae	07	Turf grass	07-Turf grass	We rely on grasses for our lawns; this is a bent grass lawn in Highland Park, Illinois.	
Poaceae	08	Bamboo	08-Bamboo	Grasses are also important in tropical regions, such as this bamboo in Jamaica. (That is Jeff Zimpfer standing by the plant). Most bamboo species are large and "tree-like". But remember that grasses are monocots, and true wood is absent.	
Poaceae	09	Grasslands	09-prairie	Grasses are also important in many natural ecosystems; the tallgrass prairie is one type of grassland.	
Poaceae	10	Sod and bunch	10-Rhizomatous grass	There are two broad categories of grasses with regard to the presence or absence of horizontal rhizomes. Grasses <I>with</I>rhizomes are called <B>sod</B> forming grasses, while those that <I>lack</I> rhizomes are called <B>clump</B> grasses.
Poaceae	11	Vegetative features	11-vegetative	V egetatively, grasses have several features. The stems are round in cross section, the internodes are hollow, the nodes are solid, the leaves are flat and 2-ranked, the bases of the leaves have an open sheath that encircles the stem, and there is often a ligule present at the juncture of the sheath and the leaf blade.	
Poaceae	12	Spikelet	12-Spikelet	The inflorescences of grasses also have distinctive characteristics. The basic unit of an inflorescence is a spikelet, which contains 1 or more flowers. At the base of the spikelet are 2 bracts called glumes. The spikelets can be arranged in panicles, racemes, spikes, or other types.	
Poaceae	13	Floret	13-Floret	 Each individual flower is subtended by 2 additional bracts, the lemma and the palea. Sometimes the lemma has a long awn at the tip. A flower plus the lemma and palea is called a floret. The lodicules are small sacs that inflate to spread apart the lemma and palea so that the anthers and stigmas are exposed to the wind for pollination to take place.	
Poaceae	14	Spikelet and floret	14-Spikelet & floret	This model of a spikelet of oats (<I>Avena fatua</I>), shows the structure of a spikelet and a floret.		
Poaceae	15	Spikelet and caryopsis	15-Spikelet/Caryopsis	This is one spikelet of wheat (<I>Triticum aestivale</I>) that is in fruit. A palea has been removed from the floret in the lower left to show the fruit, a caryopsis. A caryopsis is much like an achene, except that the seed coat is fused to the pericarp.	
Poaceae	16	Festuca spikelets	16-Festuca spikelets	Here are 4 spikelets of a species of fescue (<I>Festuca</I>).	
Poaceae	17	Festuca spikelet	17-Festuca spikelet	This photograph shows one spikelet of fescue (<I>Festuca</I>). Note the 2 glumes, the stigmas, the anthers, and the lemmas of several different florets.	
Poaceae	18	Zea mays plant	18-Zea mays plant	Perhaps the most familiar grass in Illinois today is corn or maize (<I>Zea mays</I>). The flowers are imperfect and the plants are monoecious. The male flowers are produced in tassles at the tip of the plant (yellow arrow), while the female flowers are born in "ears" (magenta arrow).	
Poaceae	19	Zea mays tassle	19-Zea mays staminate	This is a close-up of a corn tassle with many male flowers - note the anthers hanging down for the flowers.	
Poaceae	20	Zea mays young ears	20-Zea mays ears	This is a one ear of <I>Zea mays</I> that contains many female flowers surrounded by a husk of green leaves. Protruding from the end of the ear are all the styles from each individual female flower (the "silk").	
Poaceae	21	Zea mays ears	21-Zea mays ears	Here are two ears of <I>Zea mays</I> that have been removed from the husk. Note the numerous long styles (silk). Each silk connects to a female flower. The ovary of each flower matures into one "grain" or caryopsis.	
Poaceae	22	Zea mays ripe ear	22-Zea mays ear	This is a ripe ear of <I>Zea mays</I> with some of the husk leaves pulled away to show the many grains; the styles persist and turn brown.	
Poaceae	23	Big bluestem	23-Andrdopogon gerardii	 Prior to European settlement, the landscape of Illinois was dominated by prairie instead of fields of corn. One of the most common prairie grasses is big bluestem (<I>Andropogon gerardii</I>), which can be 8 feet tall.	
Poaceae	24	Indian grass	24-Sorghastrum	Another large prairie grass is Indian grass (<I>Sorghastrum nutans</I>).	
Poaceae	25	Indian grass spikelet	25-Sorghastrum	Here is one spikelet of Indian grass (<I>Sorghastrum nutans</I>), with an inset detail showing the spiralling awn. 	
Poaceae	26	Prairie dropseed	26-Sporobolus	One of the most beautiful prairie grasses is prairie dropseed (<I>Sporobolus heterolepis</I>), which forms graceful mounds about 1.5 feet in diameter. The purple and while inflorescences belong to two legume species, purple prairie clover (<I>Petalostemum purpureum</I>) and white prairie clover (<I>Petalostemum candidum</I>).	
Poaceae	27	Prairie dropseed	27-Sporobolus	In autumn, the leaves of prairie dropseed turn a beautiful orange color.