The entry form states that the lei must be 

24 inches in length, ends untied, and made to adorn the hat of a Paniolo. The lei may be entered in the "beautiful" category, comprised of only fresh all-natural materials such as flowers, seeds and feathers, or in the "unique" category in which any materials may be used!

What is a "Paniolo" you may ask? I found the perfect answer (and amazing photography) from local Maui professional camera artist Randy Jay Braun:

"The story begins in 1795, when the British Sea Captain, George Vancouver, gifted a few head of Mexican Longhorn cattle to King Kamehameha, as an offering of friendship. The King protected them, allowing them to multiply and roam the islands untouched for 40 years. Eventually, the herd grew to thousands, creating a need for instruction in handling and managing the descendents of those first few cattle. While the first horse was introduced to the islands in 1803,

Uncle Dan by Randy Jay Braun

it was not until some 30 years later that expert cattle handlers - the Spanish-Mexican "vaqueros" were brought to Hawaiʻi to teach the Hawaiians. In fact, the word "paniolo" evolved from the word "Espanol" (Spanish) that was used in the early years in referring to the vaqueros. Today, "paniolo" is a term used with well-earned respect and admiration in describing the Hawaiian, or Hawaiʻi-born, cowboy working on island ranches. Also, it's a general term used for the rural, ranch-related lifestyle in the islands. Active cattle ranches can be found on the islands of Hawaiʻi, Maui, Molokaʻi, Oʻahu, and Kauaʻi. Hawaiʻi produces over $18 million worth of beef every year. The "Big Island" of Hawaiʻi has one of the largest ranches in the world, Parker Ranch. 

Tsugi Kaiama Passing on the Art of Lei Hula Papa.