SENSITIVE AREAS OF THE EASTERN SAN GABRIEL MOUNTAINS

“Morgan Plateau”
(No official name)
Los Angeles County
East and adjacent of Morgan Canyon
Glendora

Dick Swinney
Copyright May 2005

Observations:
21 June 1991
15 May 1992
17 April 2001
19 April 2005
30 April 2005
Elevation: 1300-1400 feet
Quad: Glendora
T1N R 9W Section 27
Long. 117 degrees 49 min. 1 sec. W. Lat. 34 degrees 08 min. 37 sec. N.
Location: Approximately 0.3 miles north-east of Morgan Canyon Debris Basin in Glendora. It is east of the east fork of Morgan Canyon and immediately adjacent to it.
Description: This previously disturbed area(likely disked), had a jeep road passing through the middle of the western margin of the plateau from north to south. The entire area was set aside as open space as a result of mitigation with the California State Department of Fish and Game. This was due to the discovery of Brodiaea filifolia by Tye Garrison who was doing the Environmental Impact Report for the owners of the Guard Ranch Property. John Gordon oversaw the project and made this concession as mitigating circumstances to keep the area of highest concentration of Brodiaea preserved.
One of the upper sites for development (east of the plateau) had a much smaller population of this species. The owner was given permission to develop this through concession of the lower” Morgan Plateau” area.
As of May 1, 2005, the upper eastern flat area has been graded and all the Brodiaea filifolia were bulldozed. I took a census of this area on May 14, 1992. I counted two-hundred and thirty-two Brodiaea filifolia as well as several Calochortus spendens and Calochortus plummerae. They were mostly in full bloom at that time.
Habitat: grassy plateau surrounded by coastal sage-scrub and chaparral
Special Conditions: A truck trail previously ran through the western portion. This area has been dedicated as private “open space” as part of the mitigation with the developer relating to the presence of Brodiaea fillifolia. The dominant plants are naturalized grasses.

Name Not Present Abundance
Dicotyledons May 1992 only in: Apr.2005
Adenostoma fasciculatum R
in marginal areas
Anagalus arvensis U
Artemisia californica FC
Baccharis pilularis
one plant under Oak X R
Calandrinia ciliata VN 7873 X 2001 U
Calystegia macrostegia
ssp. intermedia U
Carduus pycnocephalus U
Centaurea melitensis U
Clarkia purpurea
Dodecatheon clevelandii VN 7875 X 2001 U
several plants in one
population in the
north-western area near
plateau edge
Epilobium canum ssp.
canum U
Erodium cicutarium A
Erigeron foliolosus var. foliolosis U
Eriogonum fasciculatum
var. foliolosum U
Euphorbia peplus 1992 R
Galium aparine FC
growing over cactus
Galium nuttallii 1992 R Geranium dissectum C
Gnaphalium californicum X U
Heilanthus annua U
Hemizonia fasiculata FC
Heteromeles arbutifolia
mostly in marginal areas U
Hirschfeldia incana A
Hypochoerus glabra
Lotus scoparius FC
Lotus strigosus? U
Malosma laurina FC
Marubium vulgare C
Opuntia littoralis U
one large population U
Phacelia cicutaria var. hispida X U
Quercus agrifolia var. agrifolia U
Rhamnus ilicifolia R
in marginal areas
Ribes amarum
Ribes aureum X U
Ribes malvacium R
one plant under Oak
Sambucus mexicana
mostly in margins U
Scutellaria tuberosa VN 7874 2001 R
Silybum marianum U
Solanum douglasii U
Toxicodendron diversilobum U
Trifolim hirtum C
Vitchia R

Monocotyledons
Alium haematochiton U 34 scapes with blossoms on
April 19, 2005
all scapes in fruit on April 30 2005
Avena barbata A
Bloomeria crocea FC
nearly100 scapes in bloom on
30 April 2005
Brodiaea fillifolia A
Bromus hordiacious A
Calochortus catalinae U in bud & bloom, 17 April 2001
39 plants in bloom, 19 April 2005
20 plants in bloom, 30 April 2005
Calochotrus plummerae U Calochortus splendens U
Chlorogalum pomeridianum FC
Dichelostemma capitatum FC
Lolium perrene A
Sisyrinchium bellum
mostly in the western area FC
Vulpia octoflora C? Vulpia myuros A


Brodiaea filifolia Observations:
21 June 1991
total number of scapes counted: 1,236
Nearly 1000 with fruit

15 May 1992
total number of scapes counted: 5,550
Sample Study: A 1 ft x 1 ft square was randomly tossed in the densest concentration of the Brodiaea in the south-west area on the plateau. Three samples were taken.

Sample # Condition # of plants Percentage (%)
1 in bloom 22 100
bud only 0 0
total 22
2 in bloom 12 100
bud only 0 0
total 12
3. in bloom 8 89
bud only 1 11
total 9

Av. % of plants in bloom:
Av. % of plants in bud only:

Total # of scapes: 43
Av. # of scapes/quad: 14.3
Av. # of scapes in bloom/quad: 14
Av. # of scapes in bud/quad: 0.02
Av. # of scapes in fruit/quad: 0


There were no scapes present with fruits only in either study listed here. The fruits were either not developing or they and their pedicils were dropping quickly as there were no scapes present with fruitless pedicils. Therefore, it made it difficult to determine the age of the persisting scapes without pedicels. They could be from the previous year as a survey of the area in the winter showed that many old scapes persisted. Therefore these were not counted in the studies.

The following 5 one-foot (quad)samples were used, this time only recording fresh scapes.
Sample # Condition # of plants Percentate (%)
1. in bloom 22 100
in fruit only 0 0
in bud only 0 0

2, in bloom 12 100
in fruit only 0 0
in bud only 0 0

3. in bloom 8 89
in fruit only 0 0
in bud only 1 11


4. in bloom 12 75
in fruit only 0 0
in bud only 4 25

5. in bloom 8 100
in fruit only 0 0
in bud only 0 0

Av. % of plants in bloom: 92
Av. % of plants in bud only: 07
Av. % of plants in fruit only: 0

Because of differentiating between this years scapes without pedicels and dried scapes from previous years, the catagory of % of this years old scapes(with dropped pedicels) was not counted. There were most likely some, therefore the average percentages are exagerated.

total scapes: 67 scapes
average # scapes per quad: 13.4
average # scapes in bloom/quad: 12.4
average # scapes in bud/quad: 1
average # scapes in fruit/quad: 0

Note:
The “in bloom” condition represents any scape with at least one pedicel in bloom.
The “past bloom” condition represents those scapes with one or more fruits and no flowers or with all the pedicels absent , or one or more pedicels present without fruit. The” bud only” condition represents any scape with only buds.
17 April 2001
vegetative only, no inflorescences
did not revisit to record data
19 April 2005
total number of scapes counted: 6,900
The scapes were mostly in bloom, some in bud only and some with inflorescense already detached. In the short, dry grass, nearly 30 % of all plants with ilnflorescenses were detached. Plants in tall green grass areas or under some canopy, nearly 30 % of all inflorescenses were in bud only. The majority of the plants were in full exposure and in dried stands of grass. Very little effort was expended to count the naked scapes of this season, therefore this is a very conservative number.

List of plants in order of abundance
1. Avena barbata A
2. Vulpia myuros A
3. Bromus hordeaceus A
4. Erodium cicutarium A
5. Carduus pycnocephalum A
6. Geranium dissectum A
7. Lolium perenne A
8. Brodiaea filifolia A
9. Hershfeldia incana C
10. Acnatherum lepida FC

% of plants naturalized: 80
% of plants native: 20



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