Carphephorus carnosus CLICK
Carphephorus carnosus has a striking appearance, the slightly succulent leaves mostly at the plant base, in low rosettes, often crowded in sizable patches, stiff and knife-shaped. The appearance suggests a desert species, or maybe something from a rock garden.
The geographic distribution is interesting too. Restricted more or less to central Florida, the species occurs in pinewoods, prairies, and low open usually moist habitats. These habitats are hardly the desert/rock garden just mentioned, except in a seasonal sense. The habitat are places of periodic fire, of blazing sun, and of poorly drained sandy soils where conditions flip-flop between seasonally soggy and seasonally xeric.
The plants seem highly adapted to fire. The dense patches of low rosettes appear to be fire-resistant: low and tough, out of harm’s way from blowing flames and blowing winds. The congested leaf islands formed by the crowded rosettes appear to offer flame-proofing like buffalo in a ring. The edges may fry, but the inner reachers are protected. The plants have a hard knotty core to which they can burn back or die back in the dry season, to regenerate fresh leaves in the summer months, culminating with flowering in the safe rainy autumn. Turning briefly to a related species, Carphephorus paniculatus is not just fire-tolerant, but also fire-dependent. The latter species has been documented to decline by 75% after three decades of fire protection. This is probably true of C. carnosus as well. These pioneer species with parachute “seeds” (achenes) can blow readily into recently burned areas.
Species of Carphephorus are glandular, with the fragrance champion being C. odoratissimus, “Vanilla-Leaf,” with vanilla-scented foliage. The most obvious explanation for the aromatic essences is protection from herbivores. Although the fragrance suggests vanilla, it differs chemically from the natural orchid extract. The volatile essences from C. odoratissimus are a mix of sesquiterpenoids (these are common in Asteraceae), miscellaneous other compounds, and, primarily, coumarin, which can smell like vanilla. Coumarin is scattered among diverse plant families as a feeding deterrent; among other effects, it suppresses livestock appetites, and converts into a toxic anticoagulant, making it useful in modern human pharmacology.
These plants undoubtedly have ecological secrets relating to their harsh habitats. Their beauty comes in large part from their stark toughness topped with rich purple flower heads. This post is the outcome of a trip to Jonathan Dickinson State Park by John Bradford and George Rogers. John took the photo.