Monographs Details: Magnolia sororum Seibert
Authority: Vázquez García, J. Antonio. 1994. Magnolia (Magnoliaceae) in Mexico and Central America: A Synopsis. 46: 1-23.
Family:Magnoliaceae
Scientific Name:Magnolia sororum Seibert
Discussion:

Magnolia sororum Seibert, Ann. Missouri Bot. Gard. 25: 828. 1938. TYPE: PANAMA. Chiriqui: Valley of the upper Chiriqui Viejo, 1300-1900 m Jul 1937 (fl, fr), White & White 21 (HOLOTYPE: MO!; ISOTYPES: GH!, MO!).

Magnolia sororum Seibert subsp. soro- rum is perhaps most closely related to the Mexican M. iltisiana and to M. grandiflora of the southeastern U.S., but differs from the former by its fewer stamens, narrower perianth parts, smaller fruits and seeds and from M. grandiflora by not only its much smaller flowers and fruits, but also its fewer carpels. Based on the conspicuous differ- ences in pubescence color and leaf shape, the species may be divided into two geo- graphic subspecies as follows:

Key to the subspecies of Magnolia sororum

Pubescence on the underside of leaves, young branches, peduncles, and (usually) poly- follicles rusty brown; leaves mostly broadly elliptic to obovate (Panama) ................................... . .......................................1. lOa. M. sororum subsp. sororum

Pubescence on the underside of leaves, young branches, peduncles, and (usually) poly- follicles pale yellow (stramineous); leaves narrowly elliptic to lanceolate (Costa Rica, rare intermediates on Volcdn Chiriqui, Panama) ......... 1 Ob. M. sororum subsp. lutea