Photo of a small, globose cactus in situ with buds and a single open, pink flower.

The definition of serotiny is sometimes expanded to include seed retention of any sort. Mammillaria pectinifera expels fruits in wet years & retains them in dry years—a bet-hedging strategy to ensure seedling establishment. 📷: Noemí Velasco Rubí CCBYNC4. #Cactaceae #serotiny #Botany 🌾🧪🌱

Photo of leafy shoots with tiny leaves and bare stems along which small, woody capsules are tightly clustered together like sleeves around the stems. Photo by Scott Zona CC BY-NC 2.0.

Melaleuca huegelii is from Western Australia. Like many Melaleuca spp., it’s a serotinous species. The fruits are retained in capsules until released by heat/fire. #Myrtaceae #serotiny #Botany 🌾🧪🌱

Photo of an erect leafy shoot with bare stems bearing globose clusters of bracts enveloping capsules, which are hidden beneath the bracts.

Check out the female inflorescences of Cliffortia conifera, a denizen of fire-prone ecosystems of South Africa. The “cones” are condensed clusters of flowers & bracts. This species is serotinous & also resprouts from lignotubers. 📷: Ismail Ebrahim CCBYNC4. #Rosaceae #serotiny #Botany 🌾🧪🌱

Photo of a woody stem bearing globose woody capsules.

Photo of a single woody capsule that has opened. The very thick walls of the capsule are visible.

These fruits of Hakea lehmanniana (📷: geoffbyrne CCBYNC4) are impossibly woody, but a bushfire will trigger the fruits to open and release the seeds. Native to Western Australia. (HT to devils.poison on IG for directing me to this sp.) #Proteaceae #serotiny #Botany 🌾🧪🌱

Photo of a scorched landscape and blackened, leafless branches bearing cone-like clusters of capsules. Many capsules are open and gaping.

Australia’s Banksia has fruits that are serotinous, opening after fire. Wildfires clear competing vegetation + deposit nutrients in the soil = good conditions for seedling establishment. 📷: Banksia ornata by davidsando CCBYNC4. #Proteaceae #serotiny #Botany 🌾🧪🌱

Photo of needle-bearing shoot with pinecones. The cones are closed.

Pinus banksiana cones are strongly serotinous in populations in the center of the species’ range, but less so at the edges of its range (where fires are less frequent). It's a bet-hedging strategy to ensure seedling establishment. 📷: Taylor Justason CCBYNC4. #Pinaceae #serotiny #Botany 🌾🧪🌱

Photo of needle-bearing shoot with pinecones. The cones are closed. Photo by Scott Zona CC BY-NC 2.0.

Pinus radiata releases seeds when the temperature goes above 45°C (113°F). Sometimes that threshold temperature can be reached by passive solar heating of the cones if they are exposed to sunlight on the tree or on the ground. They can open even without fire. #Pinaceae #serotiny #Botany 🌾🧪🌱

Photo of a pine branch with older, mature, closed cones and younger, smaller cones. The younger cones are at the distal end of the shoot. Photo by Scott Zona CC BY-NC 2.0.

Serotiny means that the seeds are stored on the mother plant, that they are retained 1+ yr (up to 10+ yr), & that high temp. (usually from fire) is involved in the release of the seeds. 📷: Pinus pinaster. Note 2 generations of seed cones on the shoot. #Pinaceae #serotiny #Botany 🌾🧪🌱

Photo of two cones attached to a branch. The pinecones are closed. Photo by Scott Zona CC BY-NC 2.0.

Serotiny is the storage of seeds in close cones or fruits, trapping the seeds & preventing dispersal until the cones are heated (usually by fire). Post-fire conditions are ideal for germinating seedlings. These are cones of Pinus clausa of the SE USA. #Pinaceae #serotiny #Botany 🌾🧪🌱