Rural Treasure Discovered

Click On Pictures For Larger View

Observations made on Pacific Union College Property, April 2011

Initial visit to site April 28, with Kellie Anderson, Paula Peterson, John Hoffnagle, John Woodbury, Jake Ruygt. Walked in at Las Posadas Road – thence Mossy Rock Trail to Inspiration Point, Redwood Flat, Mill Valley.

The area walked consisted primarily of mixed conifer forest with Douglas Fir dominant or codominant with ponderosa pine (Pinus ponderosa) and tan oak (Lithocarpus densiflorus) with some stands including coast redwood (Sequoia sempervirens). The understory is generally open with some brush (little poison oak) and perennials < 25% cover. Mountain dogwood (Cornus nuttallii), pine violet ( Viola lobata), woodland rose (Rosa gymnocarpa), canyon oak (Quercus chrysolepis) were some of the common species observed here. Some areas are brushy with common manzanita (Arctostapylos manzanita), Stanford manzanita (A. stanfordiana), Napa false indigo (Amorpha californica ssp. napensis (localized)). Walking trails vary from flat to steep sloped. The property offers access to well maintained and marked trails through second or third growth forest. Many sizable trees persist as logging may have been selective. The property is well preserved with no trash and very few artifacts of past activities.

Mill Valley is a large open meadow, perhaps ¾ mile long and 500 ft wide. The grassland is dominated by non-native grasses including rip-gut grass (Bromus diandrus) but with a prominent seasonal wetland occupies the center of the valley. Douglas’s meadowfoam (Limnanthes douglasii ssp. nivea) is dense and abundant around the wetland. Cream cups (Platystemon californicus ) is numerous in the taller upland grassland. The wetland has been invaded by pennyroyal (Mentha pulegium) but native hydrophytes are common. Some of the species observed in the meadow during the brief visit include:

Eleocharis macrostachya creeping spikerush
Eleocharis acicularis needle spikerush
Plagiobothrys sp. popcornflower
Collinsia sparsiflora ssp. arvensis blue-eyed mary
Mimulus angustatus narrow-leaved pansy monkeyflower
Lilaea scilloides flowering quillwort
Ranunculus californicus California buttercup

There is no other closely comparable valley in Napa County. Foss valley is perhaps similar in size but is surrounded in oak woodland. It contains seasonal wetlands and probably some of the same plant species but they follow narrow stream channels. The uplands there, consist of rocky outcrops. Foss Valley is threatened by proposed vineyard development making Mill Valley even more significant.

Jake Ruygt
May 3, 2011

List of Vascular Plant Species Observed in Mill Valley

Fern Allies
Isoetes howellii
Pilularia americana

Achyrachaena mollis blow wives
Agoseris retrorsa spear-leaved agoseris
Amsinckia menziesii var. intermedia common fiddleneck
Barbarea orthoceras winter cress
Calandrinia ciliata red maids
Calystegia subacaulis ssp. subacaulis hill morning glory
Camissonia ovata sun cups
Castilleja attenuata valley tassels
Cerastium glomeratum mouse-eared chickweed *
Collinsia sparsiflora var. arvensis blue-eyed mary
Downingia concolor var. concolor fringed downingia
Epilobium sp. willow herb
Erodium botrys white-stem filaree
Eschscholzia californica California poppy
Filago californica ?
Geranium dissectum cut-leaved geranium *
Gratiola ebracteata bractless hedge-hyssop
Heterocodon rariflorum heterocodon
Hypochaeris glabra smooth cat’s ear *
Leontodon saxatilis ?
Leptosiphon parviflorus common baby stars
Limnanthes douglasii ssp. nivea Douglas’s meadowfoam
Lotus humistratus hillside trefoil
Lotus micranthus San Diego trefoil
Lotus purshianus Spanish trefoil
Lythrum hyssopifolia hyssop-leaved loosestrife
Madia sp. tarweed
Mentha pulegium pennyroyal *
Mimulus angustatus narrow-leaved monkeyflower
Montia Fontana water montia
Navarretia sp.
Nemophila pedunculata meadow nemophila
Plagiobothrys cognatus
Plagiobothrys stipitatus var. micranthus small stipitate popcornflower
Plantago lanceolata English plantain *
Platystemon californicus cream cups
Pogogyne serpylloides thyme-leaved pogogyne
Psilocarphus oreganus Oregon woolly heads
Ranunculus muricatus prickleseed buttercup *
Ranunculus occidentalis western buttercup
Raphanus sativus wild radish *
Rumex acetosella sheep sorrel *
Scleranthus annuus ssp. annuus German knotgrass *
Spergula arvensis ssp. arvensis spurry *
Trifolium depauperatum var. truncatum sack clover
Trifolium dubium shamrock *
Trifolium hirtum rose clover *
Trifolium glomeratum
Trifolium microcephalum maiden clover
Trifolium subterraneum subterranean clover *
Trifolium variegatum var. variegatum white-topped clover
Trifolium wildenovii tomcat clover
Triphysaria pusilla dwarf owl’s clover
Verbascum thapsus woolly mullein *
Vicia benghalensis purple vetch *
Vicia sativa ssp. nigra common vetch *
Vicia villosa ssp. varia wolly-podded vetch *

Aira caryophyllea silvery airgrass
Briza minor little quacking grass *
Brodiaea sp. brodiaea
Bromus diandrus rip-gut grass *
Bromus hordeaceus soft chess *
Deschampsia danthonoides annual hairgrass
Deschampsia elongata ?
Eleocharis acicularis var. acicularis needle spikerush
Eleocharis macrostachya creeping spikerush
Hordeum marinum ssp. gussoneanum Mediterranean barley *
Juncus bufonius toad rush
Lilaea scilloides flowering quillwort
Vulpia bromoides six weeks fescue *