Illustrating a Dandelion Clock
Start by selecting the seed object. Click the Clusters button in the Main Command Panel (MCP) and choose the Hair cluster. Press [Ctrl] +  to switch to the Hair Toolbar. From the Create > Hair menu choose From Selection. In the Hair property editor change the number of Total hairs to 25 or so. Switch to the Effects tab and change the Root Thickness to 1.2, the Tip to 0.2 and the Random scale to 0.2. Close the property editor. Click the Scale button in the Hair toolbar and scale the hair strands so they are approximately half the length of the seed.
With the hair object selected, press  to open a Render Three. From the Nodes > Hair menu choose Hair Geometry Shading. Connect the newly created node to the Surface and Shadow input of the Material node. Double-click on the Hair_Geo_Shading node to open the PPG. Check the Use Diffuse Gradient checkbox. Select the left marker and change the color to a pale grey (roughly RGB: 0.6, 0.6, 0.6) and select the right marker and set the color to almost white (roughly RGB: 0.9, 0.9, 0.9).
Close the PPG and the Render Tree and select the seed object. Press [Ctrl] + [G] to create a group and name it seed_instance. Select the stem and click the Cluster button in the MCP and pick the Head cluster. From the Create > Hair menu choose From Selection. There are usually somewhere in the region of 50 to 170 seeds per head, so change the number of Total hairs in the hair PPG to about 80 (for the sake of interaction you’ll only cover half of the head). Switch to the Instancing tab and check the Enabled checkbox. Click the Pick… button next to the Instance Group and pick the seed_instance group. Experiment with the hair styling tools (on both hair objects) to add some natural variation and you are done.
The very same approach can successfully be used to create all sorts of vegetation, or to simplify the tedious task of covering trees and branches with leaves.