Disk flower heads

smooth bracts
184. Rayless thelesperma. Thelesperma megapotamicum
185. Slimleaf hymenoppapus. Hymenoppapus tenuifolius

shingle-like bracts
188. Ironweed. Vernonia baldwinii
190. Blazing star . Liatris punctata


recurvd bracts
191. Curlycup gumweed. Grindelia squarrosa var. nuda

spine-tipped bracts
195. Yellow-spined thistle. Cirsium ochrocentrum
196. Wavyleaf thistle. Cirsium undulatum