# Morphological variation in the Rhododendron pseudochrysanthum Hayata (Ericales, Ericaceae) species complex from Taiwan

## TL;DR

This paper identifies a distinct subspecies of Rhododendron pseudochrysanthum in Taiwan based on unique leaf, flower, and seed traits.

## Contribution

The study provides new evidence for taxonomic differentiation within the R. pseudochrysanthum species complex using morphological and statistical analysis.

## Key findings

- R. pseudochrysanthum ssp. morii var. taitunense is distinct in leaf, flower bud, pollen, and seed morphology.
- The taxon has a restricted distribution in low-elevation northern Taiwan.
- Statistical analysis confirms morphological differentiation from other members of the species complex.

## Abstract

Our study examines the morphological and statistical differentiation within the Rhododendron
pseudochrysanthum species complex through comparative analyses of macro- and micro-morphological characters. Using significance testing and cluster analysis, our results demonstrate that R.
pseudochrysanthum Hayata ssp. morii (Hayata) Yamazaki var. taitunense Yamazaki is distinct from other members of the complex, namely R.
morii Hayata, R.
pseudochrysanthum Hayata, and R.
hyperythrum Hayata. This taxon is characterized by glabrous mature leaves with revolute margins, larger flower buds with an elongated conical shape, larger pollen and seed sizes, and distinct pollen and seed morphology. Furthermore, R.
pseudochrysanthum ssp. morii var. taitunense exhibits a restricted and localized distribution, occurring exclusively in low-elevation mountainous areas of Northern Taiwan. Overall, our results indicate that this taxon has undergone clear morphological differentiation from other taxa within the R.
pseudochrysanthum species complex.