Scutellaria parvula, commonly known as the small skullcap, is a species of flowering plant in the mint family. It is native to eastern and central North America, ranging from Ontario and Quebec south and west through much of the eastern and central United States to Texas.
Description Scutellaria parvula is a small herbaceous perennial with a low growth habit. It occurs in open habitats such as prairies, meadows, open woods, and cedar glades, often on calcareous soils. Flowering takes place from late spring to early summer.
Distribution and habitat Scutellaria parvula occurs in eastern and central North America. In Canada it has been recorded from Ontario and Quebec, and in the United States from Maine west to Minnesota and south to Georgia and Texas. It grows in a variety of open or semi-open habitats, including upland prairies, rocky woodlands, bottomland forests, rock outcrops, limestone glades, diabase barrens, and shale barrens.
Ecology In cedar glades of middle Tennessee, S. parvula flowers, sets seed, and forms moniliform tubers in May and early June, after which the aerial shoots die back by late June. The species persists through both seeds and tubers. Most seeds are dormant when mature but afterripen during summer and typically germinate in late summer or autumn, producing overwintering rosettes. The tubers each bear a terminal bud that gives rise to a new shoot. In favorable conditions, some shoots may emerge in late summer and complete flowering and fruiting in autumn, but most emerge in autumn and overwinter as rosettes before flowering the following spring.
Taxonomy Scutellaria parvula was first described by André Michaux. In a 1901 taxonomic study, Merritt Lyndon Fernald distinguished a densely pubescent form corresponding to Michaux's concept of the species from a smoother form previously described as Scutellaria ambigua, and treated them as varieties rather than distinct species. NatureServe recognizes three infraspecific taxa within Scutellaria parvula: S. parvula var. australis, var. missouriensis, and var. parvula. The closely related Scutellaria australis has also sometimes been treated as a variety or closely allied species, though modern treatments generally recognize it as distinct.
Conservation Scutellaria parvula is ranked G5 by NatureServe, indicating that it is considered globally secure. Although the species has a large overall range and many occurrences, documented threats in parts of its range include development, livestock trampling, right-of-way maintenance, ecological succession, recreational disturbance, and invasive species.
Phytochemistry A 2004 study of acetone extracts from the aerial parts of Scutellaria parvula reported a previously undescribed neoclerodane diterpenoid, named scuteparvin. The authors noted that this finding supported a close chemotaxonomic relationship between Scutellaria and Ajuga.
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