{tab=Trip Recap}

We had a great trip today as we explored one of Orange County's iconic, but seldom visited locations, Irvine Lake.

Created about 1930 by constructing a dam across the face of Santiago Creek, this is now Orange County's largest body of water. It is used as a source of water to the nearby communities of North Orange County and also offers significant fishing a recreation activities.

Irvine Lake is host to several plant species that are limited to it specialized habitats. In some areas the margins of the lake mimic a vernal pool habitat and support a specific set of plants that require seasonally wet (inundated) soils following by drying, as well as mud-marginal plants: Nama stenocarpum, Ammannia robusta (valley red-stem), Echinodorus berteroi (upright burhead), Verbena bracteata (bracted vervain), Crypsis schoenoides, Persicaria lapathifolium (a smartweed),

Persicaria punctata (another smartweed), Phyla nodiflora var. nodiflora (frog-food) and Samolus parviflorus (water pimpernel). We also paused to discuss distinguishing characteristics of several species and genera in the Cyperaceae (sedges) and Typhaceae (cattails) families, including Bolboschoenus maritimus (alkali bulrush), Cyperus esculentus (yellow nutsedge), Cyperus eragrostis (tall umbrella sedge), Typha domingensis (southern cattail) and Typha latifolia (broad-lreaved cattail).

At one location we spent a few minutes understanding two easily confused small flowered asters that were growing side-by-side: Erigeron canadensis (common horseweed) and Symphyotrichum subulatum (slender aster). Another relative, Erigeron bonariensis (flax-leaved horseweed), was growing nearby.

Finally, we visited one of Orange County's few stands of Pluchea serivicea (desert arrowweed).We left the lake with a better understanding of the unique plants here. A few participants even discussed the possibility of CNPS renting one of the small houseboat type of boats and heading out sometime for a late afternoon, early evening trip around the lake, searching for aquatic plants and enjoying the wildlife and environment. Interested? Stay tuned - you never know.

{tab=Plants Seen}

Acmispon americanus

Acmispon scoparius

Ambrosia psilostachya

Ammannia robusta

Anagallis arvensis*

Artemisia californica

Arundo donax*

Atriplex triangularis (prostrata)

Avena sp.*

Baccharis pilularis ssp. pilularis

Baccharis salicifolia

Bolboschoenus maritimus

Brassica nigra*

Bromus diandrus*

Bromus madritensis ssp. rubens*

Chamaesyce albomarginata

Chamaesyce maculata*

Chenopodium ambrosioides

Cirsium vulgare*

Crypsis schoenoides*

Cuscuta subinclusa

Cynara cardunculus*

Cynodon dactylon*

Cyperus eragrostis

Cyperus esculentus

Datura wrightii

Digitaria sanguinalis*

Echinochloa crus-galli*

Echinodorus berteroi

Eclipta prostrata*

Epilobium ciliatum ssp. ciliatum

Erigeron bonariensis

Erigeron canadensis var. canadensis

Eriogonum fasciculatum

Foeniculum vulgare*

Heliotropium curassavicum

Hemizonia fasciculata

Heteromeles arbutifolia

Heterotheca grandiflora

Lactuca serriola*

Lycopersicon esculentum*

Malosma laurina

Malvella leprosa

Melilotus albus*

Mimulus aurantiacus

Nama stenocarpum

Nicotiana glauca*

Opuntia sp.

Persicaria lapathifolium

Persicaria punctata

Petunia parviflora

Phyla nodiflora var. nodiflora

Picris echioides*

Pinus halepensis*

Plantago major*

Pluchea sericea

Polypogon monspeliensis*

Portulaca oleracea*

Pseudognaphalium luteo-album*

Pulicaria paludosa*

Quercus agrifolia

Rhamnus ilicifolia

Rhus integrifolia

Ricinus communis*

Rorippa palustris

Rumex crispus*

Rumex maritimus*

Salix gooddingii

Salsola tragus*

Salvia apiana var. apiana

Salvia mellifera

Sambucus mexicana

Samolus parviflorus

Schoenoplectus californicus

Solanum americanum*

Sonchus oleraceus*

Symphyotrichum subulatum

Tamarix ramosissima*

Toxicodendron diversilobum

Typha domingensis

Typha latifolia

Verbena bracteata

Verbena lasiostachys var. lasiostachys

Veronica anagallis-aquatica*

Xanthium strumarium

* = Not native, at this location