In an experiment using a minirhizotron camera, stinkwort (left) root growth was tracked over time and compared to the root growth of yellow starthistle and the native virgate
tarweed. [Graphic omitted]
They depended o-n wild plants that grew in open prairie, such as camas,
tarweed and yampah.
"The brown is star thistle, the green is
tarweed," explains Tucker Catlin.
The researchers speculate that a single
tarweed progenitor established itself on one Hawaiian island.
Aside from the pools, Yahi's attractions include a remarkable number of brodiaea species-plus lupines, clarkias, foothill and ftying-pan poppies, Chinese houses, bird's-eye gilia, shooting stars, delphinium, lomatium, and
tarweed, as well as buttercup, monkey flower, and linanthus species.
The heavy, sweet scent of
tarweed, one of more than 50 rare upland native prairie species that once carpeted the Willamette Valley, engulfed 4-year-old Amelia Cascade on a recent morning as she explored the Walama Restoration Project's butterfly meadow.
Several of the serpentine patches were surrounded by "semi-serpentine" zones, where the soils appeared to be a mixture of serpentine and nonserpentine sediments; these zones typically supported a mix of non-native grasses and native herbs, with especially high densities of
tarweed (Hemizonia congesta and Calycadenia pauciflora, Asteraceae).
New combinations and new genera in the North American
tarweeds (Compositae-Madiinae).
Thus, coverage is broad taxonomically, geographically, and topographically, though a plethora of other spectacular cases (e.g., the Hawaiian honeycreepers and
tarweeds, Macaronesian sow-thistles and buglosses, Caribbean birds, and Sea of Cortez lizards) might merit full treatment in a second volume.
Carr (eds.),
Tarweeds and silverswords: evolution of the Madiinae (Asteraceae).
While the silversword ancestor arose from western North American
tarweeds about 15 million years ago, the present alliance of 28 Hawaiian species has evolved into its diversity of forms and habitats in the last 6 million years (Baldwin).
