New Fl. 3: 73. 1838
North America, n Mexico, ne Asia, introduced in Europe.
Species 8–10 (6 in the flora).
Some species of Physocarpus are not well delimited. Some botanists have confused Physocarpus and Neillia (including Stephanandra); Physocarpus is distinguished by its rounded umbel-like racemes and bladderlike fruits splitting along both sutures; in Neillia, the inflorescences are longer and narrower, and the fruits split along the adaxial suture. As currently understood, Neillia is an Asian genus. Two or three species of Physocarpus are widely cultivated in North America and Europe; the others are less commonly seen though they may be worthy of more attention.
Opulaster Medikus ex Kuntze is an illegitimate, superfluous name that pertains here.
|1||Carpels 3–5, connate basally||> 2|
|1||Carpels 1 or 2(3), if 2(3), connate 1/2 their lengths||> 4|
|2||Carpels densely stellate-hairy (sometimes only on sutures); follicles densely stellate-hairy (sometimes only on sutures).||Physocarpus intermedius|
|2||Carpels mostly glabrous, sometimes hairy (on ventral sutures) or sparsely stellate-hairy, glabrescent; follicles glabrous or sparsely stellate-hairy, ± glabrescent||> 3|
|3||Follicle lengths ca. 2 times sepals; leaves usually longer than wide; racemes open.||Physocarpus opulifolius|
|3||Follicle lengths slightly exceeding sepals; leaves usually as wide as long; racemes dense.||Physocarpus capitatus|
|4||Leaves 0.5–2 × 0.5–2 cm; carpels 1(2); stamens unequal (alternately long and short).||Physocarpus alternans|
|4||Leaves 1.5–6 × 2–6 cm; carpels usually 2(3); stamens ± equal||> 5|
|5||Stipules oblong to elliptic or obovate, apices of some rounded or erose, 6 × 2.5 mm; follicles flattened, keeled apically.||Physocarpus malvaceus|
|5||Stipules linear to narrowly elliptic or subulate, apices acute, 4–5 × 1 mm; follicles inflated, not keeled apically.||Physocarpus monogynus|
|Author||Crinan Alexander +|
|Authority||(Cambessèdes) Rafinesque +|
|Basionyms||Spiraea sect. Physocarpus +|
|Common name||Nine-bark + and physocarpe +|
|Distribution||North America +, n Mexico +, ne Asia + and introduced in Europe. +|
|Etymology||Greek physa, bladder, and karpos, fruit, alluding to inflated follicles of some species +|
|Illustration copyright||Flora of North America Association +|
|Illustrator||Marjorie C. Leggitt +|
|Publication title||New Fl. +|
|Publication year||1838 +|
|Source xml||https://firstname.lastname@example.org/aafc-mbb/fna-data-curation.git/src/f50eec43f223ca0e34566be0b046453a0960e173/coarse grained fna xml/V9/V9 571.xml +|
|Taxon family||Rosaceae +|
|Taxon name||Physocarpus +|
|Taxon parent||Rosaceae tribe Neillieae +|
|Taxon rank||genus +|
|Volume||Volume 9 +|