Seedling morphology in Iridaceae: Indications for relationships within the family and to related families

• Published in: Flora. Morphologie, Geobotanik, Oekophysiologie Geobotanik, Oekophysiologie, 2003, Vol.198 (3), p.220-242
• Main Author: Tillich, Hans-Jürgen
• Format: Article
• Language: English
• Subjects: Doryanthaceae; Iridaceae; Ixioliriaceae; Seedlings; systematics; Tecophilaeaceae
• ISSN: 0367-2530; 1618-0585
• DOI: 10.1078/0367-2530-00094

Iridaceae is a family of worldwide distribution and great morphological diversity. Differing from most monocot families, even the seedlings are remarkably diverse. The morphological analysis of seedlings of 36 genera revealed a good accordance of seedling types with recent molecular classifications of the family. Generally, the tribes as recently defined are homogeneous in their seedling structure. In the subfamilies Nivenioideae and Crocoideae the presumedly ancestral seedling type with compact cotyledon is dominant, only the members of tribe Croceae have cotyledons with much elongated cotyledonary sheaths and / or coleoptiles. The seedlings of Iridoideae mostly have derived states of seedling characters. The tribes Trimezieae and Tigridieae are characterised throughout by cotyledons with well developed coleoptiles. Sisyrinchieae and Diplarrheneae possess cotyledons with a long, assimilating hyperphyll. The large tribe of Irideae is diverse, but the main subclades found by molecular studies are well supported by their homogeneous seedling structures. Seedlings of the assumed sister families to Iridaceae, i.e. Tecophilaeaceae, Ixioliriaceae and Doryanthaceae, have their own specialised seedling types each and give no answer as to the seedling type of the shared ancestor.