I've had the privilege of observing the rare Pedicularis dudleyi, or Dudley's lousewort, on my 7-acre private property near Portola Redwoods State Park and Peters Creek for the past six years. This property, which is home to several hundred P. dudleyi plants, provides a unique opportunity to passively study the factors influencing the growth and reproduction of this species in its natural habitat.

The property is characterized by mature second-growth redwood forest, interspersed with Douglas fir, tan oak, and madrone. The understory is dominated by evergreen huckleberry, tan oak, and Douglas fir saplings. Scattered throughout the forest are large canopy openings created by windfalls, which allow patches of sunlight to reach the understory.

One of the most striking observations I've made is the importance of sunlight for the healthy growth of P. dudleyi. While the plants may wilt quickly when exposed to direct sunlight, this doesn't seem to have a detrimental effect on their overall health. In fact, plants that receive a few hours of direct sunlight each day tend to reach reproductive maturity more quickly, produce larger and more abundant leaves, and bear more substantial and numerous flowers compared to those growing in shaded conditions with purely indirect light.

Seed dispersal is another intriguing aspect of P. dudleyi's ecology. I've noticed that most seeds from a given flower head tend to fall in a small patch where the seed head collapses onto the ground, usually just at the edge of the plant's leaf rosette. Over time, this leads to the formation of clumps, where multiple P. dudleyi plants grow in close proximity, making it difficult to distinguish individual plants. Additionally, plants growing on steep slopes often disperse their seeds a few feet downhill, likely due to gravity or the action of runoff during rain events.

However, long-distance dispersal is also evident, as I regularly discover new plants growing dozens or hundreds of feet away from the nearest reproductive plant. I seem to find more new plants along deer trails and in more easily accessible openings in the huckleberry understory.

Herbivory by deer appears to play a significant role in the life cycle of P. dudleyi. I have frequently observed deer browsing the foliage, often nibbling entire rosettes back to the roots. In some cases, particularly enthusiastic deer have even been seen pulling up whole plants, roots and all, though this seems to be less common. Browsing occurs throughout the growing season but is most prevalent in late summer and early fall, when entire clumps may be reduced to ground level.

Herbivory can hinder the long-distance spread of P. dudleyi, especially when isolated reproductive plants are consumed after flowering but before seed dispersal. In such instances, the plant usually grows back the following year, but is smaller and may not flower again for 1-2 years after being eaten. For plants along frequently used deer trails, this can significantly delay effective reproduction and clump formation.

Lastly, I have occasionally encountered P. dudleyi plants growing in several inches of needle duff, with seedlings also appearing around mature plants in these conditions. While these environments typically receive less sunlight and support less vigorous populations, it is evident that P. dudleyi can still persist in such settings.

Based on my observations, I believe that old-growth canopy structure and a sparse huckleberry understory provide the optimal conditions for P. dudleyi. The relative density of second-growth stands, which often feature a more closed canopy and denser understory, may have had a detrimental impact on the species in its historic range. Similarly, undisturbed huckleberry thickets appear to be less favorable for P. dudleyi growth and reproduction. A sparser understory, whether created by fire, as suggested in the literature, or potentially maintained by the activities of now-extirpated large mammals such as elk and grizzlies, seems to be the preferred habitat for this rare species.