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Aquatic and Wetland Vascular Plants of the Northern Great Plains

41. Lamiaceae, the Mint Family

3. Physostegia Benth. -- Obedient plant

1. Physostegia ledinghammii (Boivin) Cantino


Similar to and in most respects intermediate between the following two species, distinguished only by a combination of characters: Leaves serrate, the upper ones clasping the stem. Corolla 14-23 mm long, puberulent and usually lacking stipitate glands. Nutlets 2.8-4 mm long. Jul--Aug. River and stream banks, shores, floodplains and ditches; rare, with records from Burleigh and McLean cos., ND; (Man. and w ND to Alta.).

Cantino (op. cit.) has determined that this entity, formerly recognized as P. virginiana var. ledinghamii Boivin, is probably an allotetraploid derivative of a cross between P. virginiana and P. parviflora. The intermediate nature of P. ledinghamii and its doubled chromosome number lend credence to this view. Because it is essentially reproductively isolated from P. virginiana and P. parviflora, recognizing P. ledinghamii as a distinct species is well justified despite morphological overlaps with the former two species.

GIF- Distribution Map

Map key


Previous Section -- Mentha arvensis L. -- Common mint
Return to Family -- Lamiaceae - The Mint Family
Next Section -- Physostegia parviflora Nutt. ex A. Gray

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