Paulownia

Keys in Flora of China are as below:

4 (1)	Capsule oblong to oblong-ellipsoid, 6-10 cm; pericarp woody, 3-6 mm; inflorescences subcylindric; corolla ventral plaits inconspicuous; calyx 2-2.5 cm	4 Paulownia fortunei
+	Capsule ovoid, ovoid-ellipsoid, or ellipsoid, 3-5.5 cm; pericarp not woody, to 3 mm; inflorescences pyramidal or narrowly conical; corolla ventral plaits conspicuous; calyx to 2 cm.	(5)

5 (4)	Capsule viscid-glandular hairy; calyx lobes as long as or longer than tube, not glabrescent	1 Paulownia tomentosa
+	Capsule pubescent when young; calyx lobes shorter than tube, partly glabrescent.	(6)

Paulownia tomentosa Steud. (Introduced) (China (Anhui, Gansu, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Liaoning, Shaanxi, Shandong, Shanxi, Sichuan), Japan (I), South Korea, Hungary (I), Italy (I), Croatia (I), Slovakia (I), Taiwan (I), Uzbekistan (I), Tajikistan (I), Pakistan (I), Jammu & Kashmir (I), USA (I) (Alabama (I), Arkansas (I), Connecticut (I), District of Columbia (I), Delaware (I), Florida (I), Georgia (I), Illinois (I), Indiana (I), Kentucky (I), Louisiana (I), Massachusetts (I), Maryland (I), Missouri (I), Mississippi (I), North Carolina (I), New Jersey (I), New York (I), Ohio (I), Oklahoma (I), Pennsylvania (I), Rhode Island (I), South Carolina (I), Tennessee (I), Texas (I), Virginia (I), West Virginia (I)) as per Catalogue of life)