Abstract Detail

Systematics Section/ASPT

Ahedor, Adjoa R. [1], Elisens, Wayne [2].

Morphological and clinal variation in Mecardonia acuminata (Plantaginaceae) species complex.

Mecardonia acuminata is a widespread endemic species in the southeastern USA. It is a wetland indicator species comprising three subspecies. Identification of the subspecies; acuminata, microphylla and pennisularis is problematic in ranges where two or three subspecies overlap. The current study employed morphological multivariate analyses to determine diagnostic features of each subspecies as well as determine latitudinal or longitudinal effects on morphology. For all three subspecies, leaf length was found to increase with increasing latitude. Therefore, leaf size is not a reliable diagnostic character for any particular subspecies including penninsularis that originally was identified by small leaves in Florida. Dendriform at base habit was found to be a more reliable diagnostic character for penninsularis. Short peduncle at both flowering and fruiting were good diagnostic characters for microphylla. No unique diagnostic character was identified for subspecies acuminata. Previous botanists reported two types of habits in the species complex; dendriform at base for peninsularis, and dendriform at midpoint for the remaining two subspecies. In this study a third habit, an intermediate was identified. Discriminant function analyses and Wilk’s lambda estimates suggested moderate to low clinal variation in some morphological characters, and a much broader historical range distribution for penninsularis. The results indicated possible backcrossing of microphylla and penninsularis into accuminata. It also suggested complex evolutionary processes masked by distinct inconsistent morphological characters. The morphological variation of the species complex may be due to secondary contact with ongoing integration of peninsularis and microphyla into the widespread subspecies acuminata particularly in areas where their ranges overlap.

1 - Rose State College, Engineering And Science, 6420 S.E. 15th Street, Midwest City, OK, 73110, USA
2 - University Of Oklahoma, Department Of Botany And Microbiology, 770 Van Vleet Oval, Norman, OK, 73019, USA, 405/325-6281

Keywords:
Mecardonia acuminata
peninsularis
microphylla
multivariate analyses
clinal variation.

Presentation Type: Oral Paper:Papers for Sections
Session: 47
Location: Salon 3/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 4:30 PM
Number: 47012
Abstract ID:618
Candidate for Awards:None