Skip the navigation header

K-State Logo K-State Research and Extension logo
go to Research and Extension home page go to News go to Publications and Videos ask a question or make a comment search the Research and Extension site

body

Sunflower Scene Logo  
May June July
August September October

July 21

July 7

July 13

July 18

July 21

July 23

July 25

July 29

 

 

 

General view July 21, 2003 Our field has been blooming now for about 5 days. People love to look at a blooming sunflower field. A lot of people have been stopping to take pictures and walk through the field. As you can see, there's a wide range of blooming stages across the field.  We'll be looking more closely at that later. 

R5.5 stage sunflowerThis plant is at the R5.5 stage, which as you probably remember R5 means it's blooming and the .5 means that 50 percent of the head has bloomed or is blooming.  Let's look a little closer at this plant. 


R5.5 stage sunflower cross sectionThis is a cross-section of the R5.5 head. On the outer edges you see white columns with their floral parts above. These are flowers that have been pollinated and seeds are developing.  In the center there are smaller columns, which are flowers that haven't bloomed yet, so they are unpollinated flowers. The base of the head is called the receptacle with its white, starchy, pithy area under the flowers. 


R5.5 stage sunflower closeupNow, we're taking a closer look at about 6 rows of flowers on the outer edge that have been pollinated and you can see the seeds or botanically, achenes developing. To the left you see about 4 rows of flowers with their stigmas emerged and then the unpollinated flowers in the center of the inflorescence.  


Seeds from R5.5 stage sunflowersThe flower on the left is from the head's center area, which hasn't bloomed yet and on the right, this seed is from the first six rows of flowers. 


R5.6 stage sunflowerThis plant is at the R5.6 stage. 

 


R5.7 stage sunflowerThis plant is at the R5.7 stage. 

 


R6 stage sunflowerThis plant is at the R6 stage. R6 is the stage at which flowering is completed and the ray petals are starting to wilt. 


R6 stage sunflower cross sectionThis is a cross section of the R6 plant. You can see stigmas of flowers in the center. So, this would be considered an early R6 plant because it is flowering today. 


R6 sunflower cross section seedsHere's the range in seed or achene development. On the left is the flower from the center with the exposed stigma and on the right is a seed from the outer area that flowered 4 or 5 days ago. 


Off-type sunflowerThere's always one in a crowd, huh? This is an off-type plant. Why is this plant different from the others? Good question.  Well, in the seed hybridization process there are plants used as the pollen source for plants from which seed is saved.  Seed from the pollen-providing plants is not saved. However, sometimes a stray seed finds its way into the saved seed. This is the result.