TAXONOMY OF THE CUSCUTA SALINA-CALIFORNICA COMPLEX (CONVOLVULACEAE)

2006·12.3 MB·English

by  Mihai Costea

TAXONOMY
OF THE CUSCUTA SALINA-CALIFORNICA
COMPLEX (CONVOLVULACEAE)
Guy L Nesom
Mihai COStea
(corresponding author)
Department of Biology Botanical Research Institute of Texas
509 Pecan
Wilfrid Laurier University Street
75 University Avenue West Fort Worth^ Texas 76102-4060, U.S.A.
[email protected]
Waterloo, Ontario
N2L3C5XANADA
[email protected]
Sasa Stefanovic
Department
of Biology
University of Toronto at Mississauga
Road
3359 Mississauga
Mississauga, Ontario
1C6XANADA
L5L
ABSTRACT
The Cuscuta californica complex (Cuscuta subsect. Calijornicae) recircumscribed to include the
is
species from subsect. 5ubi)^clusae. The species include C. sallna, C. susksdorfii, C. californica, C.
occidentalis., C. suhlnclusa, and C. howcJUanch A summary of relevant taxonomic information is pro-
vided, along with a key to species and varieties, synonymy, distribution, host range, and conserva-
tion status. Morphology and micromorphology of flowers, seeds, and capsules are analyzed and il-
lustrated.
RESUMEN
El complejo Cicscuki !i/ornica (Cuscuta subsect. Californicae)cstacircunscrito a incluir las especies
Lci
C
de subsect. Sulnnclusae. Las especies incluyen C. salina, susksdorfii, C. calijornica, C. occidentalis,
C
C. suhinclusa, y howelliana. En este trabajo se presenta un rcsumen de la informacion taxonomica
junto con una clave para identificar las especies y variedades, sinonimos, distribucion, variabilidad
de huespedes y estate de conservacion. Se analizan e ilustran la morfologia y micromorfologia de las
flores, de las semillas y de las capsulas,
and
Yuncker described and defined Cuscuta subsect. Calijornicae subsect.
(1932)
Suhinclusae mainly on the basis of absence or presence, respectively, of
He both were derived indepen-
infrastaminal suggested that sections
scales.
dently but in parallel from subsect. Arvenses. In Yuncker's view, subsect.
&
C
C
Calijornicae comprised five species: californica Hook. Arn., occidentalis
and C.sandwichiana Choisy
hrachycalyxYuncktr, Cjepsonii Yuncker,
MiUsp.,
C.
C
Engelm.,
while subsect. Suhinclusae included three species: salina C.
&
C
and Durand Hilgard (Yuncker
Yuncker, suhinclusa 1932, 1965).
sulzsdorfii
Cuscuta Rubtzoff was recently described (Rubtzoff 1966) and noted
ho\A/elliana
J
"/'
SIDA22(1):177-195.2006
178 BRIT.ORG/SIDA 22(1)
among
and
Definitions interrelationships these taxa arc complex. Beliz
C C
and
(1993) included Cuscuta hrachycalyx, occidentalis, suhsdorfii as syn-
C
C
onyms
Engelm. Cuscuta and
of calijornica var. hrevijlora suhinclusa
howcllia na were hypothesized to be sister species in a separate clade (Beliz 1986).
Some taxa were described in one subsection and later were reclassified in the
Engelmann
other. For example, (1859) initially described salina as
C. "?C.
and
calijornica var. squamigera'' as C. suhinclusa var. ahhreviata (see also the
C
example below Cuscuta sandwichiana Costea
of suhsdorfii). (Beliz 1986; et al.
2006a) and C.jepsonii (Beliz 1986; Costea et 2006c) do not appear to be evo-
al.
lutionarily related to this group.
Circumscriptions of these taxa and an assessment of their relationships
are provided here on the basis of the morphology and micromorphology of flow-
and
Conservation
ers, capsules, seeds, pollen. status is assessed for all taxa.
METHODS
Descriptions morphology Costea 2006a) based on samples from
of (see et al are
.
UC
specimens of the NY, JEPS, and herbaria (Appendix Measurements and
1).
pictures were taken with a scanning electron microscope Hitachi S-570 at 15
KY nm
K
Saniples were coated with 30 gold using an Emitech 550 sputter coater
Conservation status was determined using NatureServe (2005) ranks and
criteria.
TAXONOMY
Deliniilation of the Cuscuta salina- omica complex
calif
Our and
observations suggest that the species of subsections Californicae
We
form
Suhinclusae single phylogenetic group. hypothesize that
a
infrastaminal scales have undergone a gradual reduction from fmibriate scales
C C
or ridges in salina, to dentate wings in suksdorfii, to complete reduction in
C
A
and
californica occidental similar reduction of infrastaminal scales
C.
ls.
m
C
has occurred ndccora complex (subsect. Indccorae Yuncker) (Costea
et
al.
i
C
and
2006c). Cuscuta suhinclusa howelliana have well-developed infrastaminal
scales and were suggested by Beliz (1986) to form a distinct clade in which a
cylindric-campanulate corolla has evolved as a specialization to butterfly pol-
C C
Although and
lination. suhinclusa howelliana are distinct in their
microreticulate pollen (see descriptions belowO, close similarities in morphol-
ogy and micromorphology and
of calyx, corolla lobes, seeds, capsules (see be-
C
same
lowO indicate that they probably belong to the phylogenetic group as
A
californica, Csalina, and suhsdorfii. cylindric-campanulate corolla some-
C.
C
and Engelmann many
times occurs in californica, (1876) noted that "in re-
spects [C salina] is intermediate between the preceding califirnica] and the
[C.
following species [C suhinclusaV Yuncker (1932, 1965) observed that the corolla
of C. suhinclusa is "usually showing horizontal ridges between the stamen at-
COSTEA ET AL.JAXONOMY OF CUSCUTA SALINA-CALIFORNICA COMPLEX 179
C
we
tachments" and some
find this characteristic in flowers of callfornica as
The
well. original description of howelliana (Rubtzoff 1966) noted that
C. it is
C
similar suksdorjii suhpedicdlata.
to var.
Cuscutajepsonii and C.sandwichiana were included by Yuncker
(1932) in
m
subsect. Calijornicae (the latter species omitted the treatment from 1965)
because they exhibit a similar reduction of the infrastaminal scales. Cuscuta
may
com-
jepsonii, however, be evolutionarily related to taxa of Cuscuta indecora
plex (Costea 2006c). Cuscuta sandwichiana Hawaiian endemic and
et a
al. is
was hypothesized by Costea et al. (2006a) to belong to the C. pentagona com-
plex.
In conclusion, the Cuscuta salina-californica complex in our view includes
C
and
salina, susksdorfii, californica, occidentalism suhinclusa,
C. C. C. C. C.
which Ca Yuncker
howel/iana, are recognized here as Cusciita subsect. rn icae
[i/o
(including subsect. Suhinclusae). Taxonomically and nomenclaturally problem-
atic species are discussed below.
—
Cuscuta subinclusa. Curran (1885) noted that "from the description, [C
C
name
ceanothi evidently suhinclusa,'' and the former has been used by most
is]
From
authors Yuncker 1965) because has priority. Currants observation
(e.g. it
C
can be inferred that the type collection of ceanothi was not available even
it
may
at 1885. This collection have been destroyed during the fire following the
San Francisco earthquake from 1906 even an As observed by
or at earlier date.
C
name
Beliz (1986), possible that the ceanothi refers to a species distinct
it is
C
from The
subinclusa. protologue of ceanothi states that flowers are urceolate
C.
C
with obtuse calyx lobes, features not encountered in subinclusa or in any
Engelmann
hypothesized be addressed
species to closely related. In a letter to
Nov know
on 10 1860 (Ertter 2003), Behr wrote: "Of Cuscuta two kinds, the
I
common
one quite on Salicornia (C salinal), the other climbs on Ceanothus. Of
the latter gave once a diagnosis in the transactions (Proc. Calif.) under the pre-
I
name
liminary Cuscuta ceanothi. This diagnosis by the nature of a search
is
very incomplete, as For comparison had only the just-mentioned parasitic kind
1
summary
on and none more
the Salicornia of the closely related exotics." In a
of the San Francisco flora (1888), approximately three decades after describing
C C C
ceanothi, Behr mentioned subinclusa but not ceanothi. Without
way
no
neotypification, there apparently establish the identity of
to C.
is
C
and more might
ceanothi, until certainty exist that ceanothi not a distinct
is
C
and we name known
evidently rare species, use the later subinclusa for the
species.
—
Cuscuta Yuncker described Csa Hna var acuminata Yuncker,
suksdorfii. (1921)
C
which
he later (1932) treated at specific rank as suhsdorjii. This species
is
C
with from which morphology calyx
"closely allied salina'' differs in the of
it
and corolla, infrastaminal scales reduced to dentate wings, and multiseeded
180 BRIT.ORG/SIDA
22(1)
C C
capsules. Beliz (1986) originally treated suksdorfii as a variety of salina,
C
synonym
but she included var
later (1993) as a of calijornica hrcvijlora,
it
C
with and
together occidcnialis hrachycalyx. Indeed, shares
C. C. suks,dorJii
some
characteristics with both salina presence of infrastaminal scales
C.
(e.g.,
C
and morphology~scc and
as well as seed pollen descriptions) caJifornica/C.
we
Occident alls multiseeded capsules), but consider that treating at spe-
(Q.g., it
rank morphology and
cific better represents the differences in biology as well
as the evolutionary relationships between all the taxa involved (see below).
Cuscuta suhsdorji var suhpedicellata Yuncker with flowers sessile or subsessile,
i
mm
shorter calyx (1.6-2 long) and capsule globose to depressed globose,
is
treated formally varietal rank.
at
—
C
descnbmg
Cuscuta and Yuncker
califoriiica C. occidentalis. By hrachycalyx,
(1932, 1965) obscured the already tenuous distinction between californica
C.
C C
and occidentalis. Although homotypic, californica hrachycalyx
var.
Yuncker and hrachycalyx have slightly different protologues. Cuscuta
C.
calijornica var hrachycalyx has "corolla campanulate, lobes shorter than the
...
C
tube (Yuncker hrachycalyx has campanulate-globose,
1921, 62); "corolla
..." p.
between stamen
saccate the attachments, lobes shorter than or about equal-
...
ing the tube" (Yuncker 1932, 159) and "is closely related to C. californica, but
p.
dilfcrs by its very short calyx and more obtuse perianth lobes." Yuncker did not
mention would
the saccate corolla that separate hrachycalyx from
C. C.
hut would bring Not
californica th'di close to Coccidentc?/is. surprisingly, Beliz
it
concluded names proposed numerous and
(1986) that the perianth an-
"all for
C
ther size variants within californica do not w^arrant taxonomic recognition
C C C
and she included both occidentalis and hrachycalyx as synonyms of
/'
...
We
califv-nica var hrcviflora (Beliz 1986, 1993). find that indeed two different
C C
major entities, corresponding to caUfornica and occidentalis, can be dis-
tinguished most based on combination
in cases, a of characters. Plants called
C.
mm)
hrachycalyx by Yuncker, with a short calyx and a long (ca. 2.5 campanu-
may
become somewhat
late corolla tube that saccate in possess the
fruit, all
characteristics of C. calfornica (see belowO. Although such plants are occasion-
may
ally distinct, at other times the calyx/corolla tube ratio vary even on the
same plant, from flowers with calyx ca. equaling the corolla tube to flowers
with calyx ca. 1/2 of the corolla tube length (Fig. Apparently the co-
1 a, b, c).
may
tube continue grow from beginning
rolla to the of anthesis until fructifi-
between and
cation, significantly altering the ratio calyx corolla tube lengths.
Similar infraspecific variation of the ratio between calyx and corolla tube
may
lengths be encountered in C.gronovii (betw^een gronovii and
var. var.
latiflora Engelm.), but here the entities are relatively discrete (Costea
et al.
C
C
2006b). For these reasons, hrachycalyx here considered conspecific with
is
californica and not recognized any rank.
at
JAXONOMY
COSTEA ET AL. OF CUSCUTA SALINA-CALIFORNICA COMPLEX 181
Fig. 1. Morphology of flowers and capsules, a-c. Cuscuta californka var. californica. Variation of corolla tube length in
—
= =
flowers ofthe same individual (scale bar }n\r[]].d,C.ocddentolis flower (scale bar 1 mm).e.C.5u/fsrfor/7/- calyx
= =
(scale bar 0.75 mm).f. Papillae on corolla of howelliana (scale bar 7 jim).g-h. Capsules surrounded by corolla:
C. g.
=
mm).
californica, h. occidentalis (scale bar
C. C. 1
182 BRIT.ORG/SiDA 22(1)
Some plants of this complex produce a short (1.5-2 mm), campanulate-glo-
m
C
and
bose corolla tube (as in Cuscuta occidcntalis) long anthers/styles (as
may
show
californica), or plants reversed character states (corolla tube long
and campanulatc and Such
anthers/styles short). intermediate-like plants oc-
1-2%
cur at a frequency of ca. of specimens examined. unclear they are
It is if
which documented
resuU of hybridization, has never been clearly in Cuscuta,
or evidence of variation in closely related and incompletely differentiated taxa.
Because such possibly intermediate plants are relatively few, and to avoid no-
C C
we
and
menclatural changes, tmaintain calijornica occidcntalis as distinct
C
species. Several varieties within calijornica usually can be distinguished,
based on single characters. Cuscuta occidcntalis less variable; a few collec-
is
were found
tions to possess papillose flov^^rs like C. calijornica var. papillosa,
but the origin oi this variation unclear
is
KEY TO OF THE CUSCUTA SALINA-CALIFORNICA COMPLEX
SPECIES
Infrastaminal scales present (sometimes reduced to ridges), fimbriate.
1.
mm
Flowers 5-7(-9) long; calyx ca. 1/2 of the corolla tube, with lobes overlap-
2.
mm
ping at base; corolla lobes 1/4-1/3 as long as the tube; anthers 0.8-2 long
3.C.subinclusa
mm
somewhat
Flowers 2.8-5(-6.) long;calyx ca. equaling or longer than corolla
2.
±
tube, with non-overlapping lobes; corolla lobes equaling the tube; anthers
mm
0.3-0.7 long,
Flowers 5-merous;calyx and corolla lobes acute to acuminate;capsules
3. ellip-
±
tical-ovate, thickened around the interstylar aperture, with seed C. salina
1
1 .
.
some
Flowers 4- and 5-merous; at least calyx and corolla lobes in the same
3.
flower long-attenuate, capsules globose to slightly depressed, not thickened
with 1-4 seeds 2.C.howelliana
apically,
Infrastaminal scales completely absent or represented by dentate wings.
lateral,
1.
Flowers 4-5-merous;calyx and corolla lobes long acumlnate;infra5taminal scales
4.
represented by lateral, dentate wings; withered corolla sui rounding capsule in
lower 4.C.suksdorfii
half
"le
Flowers 5-merous;calyx and corolla lobes acute but not acuminate;infrastaminal
4.
scales completely absent; withered corolla completely enveloping the capsule
or leaving only top visible.
its
Flowers short-pedicellate; corolla not saccate between the stamen attach-
5,
ments
slightly saccate then with the following characteristics); styles
(if all
mm mm
1.2-3 long;anther5 oblong to 0.7- long; capsule completely
linear, 1.1
enclosed by corolla (top not visible); seeds not visible through the corolla
and pericarp, which are thicker, not semitransparent S.C.californica
Flowers sessile or subsessile;corolla saccate between the stamen attachments,
5.
mm
mm;anthers
styles 0.5-1 (-1.5) broadly-elliptic,0.25-0.5 long;capsule not
completely enclosed by corolla (at least the top of capsule visible); seeds
is
visible through the thin and semitransparent corolla and pericarp 6.C.
occidentalis
&
WH.
1. Cuscuta salina Engelm. in Brewer, Watson, A. Gray, Bot. Calif. 1:536.
S.
&
1876. Grammlai salina (Engelm.) Taylor MacBryde, Canad.J. Bot. 56:186. 1978. Lhctotypc
COSTEA ET AL, TAXONOMY OF CUSCUTA SALINA-CALIFORNICA COMPLEX 183
U
(Yuncker 1932): U.S.A. AH; Rio Virgen, on Suaeda, saline Nov 1885, Rcmys.n. (MO, frag-
soil,
i
ment NY). This was essentially a renaming at specific rank (as X. salina, Hngelrn. n. of
sp.^')
C
what Engelmann had earlier published as C.suhincJusa var ahbreviata and calijornica
var.
a—
squamige hoih were synonymy, Yuncker
r varieties cited in (1932) specifically referred to
MO
the specimen ("Remy, in the herbarium of the Missouri Botanical Garden") as the type of
C. salina.
Stems slender, orange-yellow. Inflorescences umbellate cymose pedicels
clusters;
mm
0.5-2.5 long; bracts l(-0), ovate-lanceolate to lanceolate. Flowers 5-merous,
mm
white, 2.5-5(-6.2) long; papillae present or absent in the corolla; laticifers
conspicuous in the perianth, ovary and capsule. Calyx campanulate narrow-
to
campanulate, about as long as the corolla tube, divided 1/2 the length, glossy
ca.
when
yellow or brownish dried, lobes ovate-lanceolate, acute acuminate,
to ±
mm
overlappmg
unequal, not basally or slightly Corolla 2.4-4.8(-6) long;
so.
mm
tube cylindric-campanulate to campanulate, L2-2.5 long, lobes ovate-lan-
ceolate, acute to acuminate, ca. as long as the tube, erect to spreading, some-
times basally overlapping. Stamens included or exerted, anthers 0.3-
elliptical,
mm
0.7 long, filaments equaling to longer than anthers. Pollen 3(-4)-zonocolpate
19-22(-26) polymorphic, subsphaerical subprolate, rounded
to at poles,
i^m,
tectum perforatum, puncta, 0.3-0.5 jam diameter, granulate
in (Fig. 2a).
Infrastaminal scales oblong, short-fringed, rarely reduced to sparingly fringed
mm
/2-2/3
ridges ca. f the corolla tube length. Styles distinct, 0.4-1 long; stigmas
mm,
capitate, globose. Capsules elliptical-ovate, 2-3.6 x 1.4-2.1 ± thickened
around the interstylar aperture, indehiscent or irregularly dehiscent, surrounded
or capped by the withered corolla. Seeds per capsule, not visible through the
1
mm,
and com-
persistent corolla pericarp, 1.35-1.57 x 1.25-1.43 ± dorsoventrally
pressed, broadly elhptic subround, hilum subcerminal, subround, 011-0.14
to
mm, mm,
X 0.7-0.11 vascular scar 0.02-0.05 oblique; surface of seed coat
linear,
when and when 30-40
epidermis alveolate dried papillate hydrated, |im
cells
&
in diameter, n - 14 (Beliz 1986); 2n = 30 (Pazy Plitmann 1995).
KEY TO VARIETIES OF CUSCUTA SALINA
Papillae present on pedicels, calyx and/or corolla; infrastaminal scales represented
1.
by narrow, sparingly fringed ridges Ic.C. salina var papillata
Papillae absent;infrastaminal scales narrowly oblong, fewToothed.
1.
mm;
2
Corolla 2-3.5 inland salt flats a. C. salina var. salina
1
mm;
2. Corolla 3-4.8(-6) coastal salt marshes, tidal flats^ lb. C. salina var, major
Cuscuta var
la. salina salina. Cuscuta subinclusa var abbreviata Engelm., Trans. Acad.
Sci.
Louis 1:500. 1859. TvpE: U.S.A. California. [Solano Mare Island in San Francisco Bay,
St. Co.]:
on Arthrocnemum, Wright (holotype: MO).
s.n.
&
Cuscuta calijornica Hool<. Arn. var squamigcra Engelm., Trans. Acad. Sci. St. Louis 1:499. 1859.
Cuscuta salina var squamigera (Engelm.) Yuncker, Illinois Biol. Monogr. pt. 2-3:71, fig. 126.
6,
Utah:
1921.Ct(.sTiif(:[sqiun7]igera(Engelm.)Piper,Contr.U.S.Nat].l-Ierb. 11:455, 1906. TYPr::U-S.A
Rio Virgen, on Suaeda. saline Nov Remy (holotype: isotype: MO, fragment
soil, 1855J. s.n. P;
Engelmanns
NY). protologue noted Rcmy\ Hb. Mus. Yuncker
specifically in Paris." (1921)
7-
m
(Remy
described the cype of var. squamigera as "Rio Virgen, 1855, a fragment in the En-
...
184 BRIT.ORG/SIDA 22(1)
=
FiG.2. Morphology of pollen. a. C£/5fuffl 5(7/™ (scale bar 10 jam).b.Cocc/Jenfa//5 (scale bar
= =
(scale bar 10 and 3 jim, respectively), e-f. C.subindusa (scale bar 10 and 3 jam, respectively).
C05TEA ET AL.JAXONOMY OF CUSCUTA SALINA-CALIFORNICA COMPLEX 185
gelmann
Herb.)."
CANADA:
Distribution and ecologjy— British Columbia. U.S.A.: Arizona, Cali-
New
MEXICO:
fornia, Nevada, Mexico, Oregon, Utah, Washington. Baja Califor-
Centromadiajaumea,
nia. Flowering Apr-Nov. Hosts: Atriplex, Cressa, Plan-
tago, Salicornia, Salsola, Suaeda, Trichostema, Wislizenia, in inland salt flats,
marshes, ponds.
T4
Conservation status.— (apparently secure) (not yet assessed by
NatureServe
2005).
lb. Cuscuta salina var. major Yuncker, Illinois Biol. Monogr. 6:161. 1921. Type: U.S.A.
California. Santa Clara Co.; Palo Alto, frequent on Salicornia in the marshes, 14 Sep 1901,
Ba}zcr41 (holotype: NY; isotypes: CAS, GH, RSA).
Distribution and ecology— CAISADA: British Columbia. U.S.A.: California, Or-
egon, Washington. Flowering Jul-Oct. Hosts: various species, especially
Salicornia, in coastal salt marshes, tidal flats.
T3T4
Conservation status.— (vulnerable to apparently secure) (not yet as-
by NatureServe
sessed 2005).
Club
Ic. Cuscuta salina var. papillata Yuncker, Bull. Torrey Bot. 69; 543. 1942.
Type: U.S.A. California. Mendocino Co.; Fort Bragg, 8-16 Aug 1912, Eastwood 1593 (holotype:
GH, fragment NY).
Distribution and ecology.— U.S.A.: Arizona, California, Utah. Floweringjun-Oct.
Hosts: various species in salt marshes, flats, ponds.
T3T4
Conservation status.— (vulnerable to apparently secure) (not yet as-
by NatureServe
sessed 2005).
W
Cuscuta howelliana Rubtzoff Leaf
2, Bot. 10:335. 1966. Type: U.S.A. California.
1.
,
Lake Co.; Boggs Lake, open dry margin of the lake, inundated in winter, 20 Aug 1966, Rubtzoff
&
Arnaud 5792 (holotype: CAS, ISOTYPES: CAS, GH, OSC, RSA, UC).
±
many-flowered
Steins slender, yellow to orange. Inflorescences few- to
mm
glomerulate cymes, pedicels 0-0.6 long; bracts 1-0, lanceolate. Flowers
mm
embedded
in the inflorescence of the host, 4-5-merous, 3-4.5 long, whitish,
and
papillate-glandular. Papillae present in the calyx corolla; elongated latici-
fers present in the calyx and corolla but not obvious (Fig. Calyx campanu-
If).
late, ca. equaling corolla tube or exceeding divided 1/2-2/3 to the base, lobes
it,
unequal, triangular-ovate, acute, acuminate to long-attenuate and recurved at
more
the apex, non-overlapping. Corolla tube cylindrical-campanulate, later
mm
or less urceolate, ca. 1.5-2.2 long, lobes unequal, ca. equaling the tube, tri-
angular-ovate, with acute to long-attenuate, recurved tips, suberect to spread-
mm mm
Stamens included, anthers 0.4-0.7 long; filaments 0.1-0.4
ing. elliptical,
long. Pollen 3(-4)-zonocolpate (15-)17-22(-24) |im, polymorph, sphaerical to
more common), rounded tectum perforatum
subprolate (subsphaerical
at poles,
to microreticulate, puncta, 0.4-0.8 in diameter, granulate (Fig. 2 d).
iiim c,
186 BRIT.ORG/SIDA
22(1)
Iiifrastaiiiinal scales oblong-ovate, fringed, reaching to about the middle of the
mm;
evenly stigmas
corolla tube; Styles distinct, filiform, 0.4-f.f capitate, glo-
mm,
bose. Capsules globose to slightly depressed, 1.2-1.5 x 0,8-1.2 not thick-
ened apically indehiscent or irregularly dehiscent, completely enclosed by the
withered corolla and latter capped by Seeds 1-4 per capsule visible through
it.
mm,
and
the semi-transparent corolla pericarp, 0.9-1.43 x 0.8-1.3 dorsoventrally
compressed subround hilum subtermi-
to slightly angled, to broadly-elliptic,
from
broadly
nal, scar area clearly difierentiated the rest ol the seed, elliptic
mm, mm,
hilum
0.21-0.25 X 0.12-0.15 linear 0.05-0.06 vertical; heterogeneous;
some with 35-50 some
areas are alveolate cells in diameter; areas irregu-
|.uti
wrinkled In = 26 (Behz
larly (Fig. 3 1986).
c, e, f, g).
m
Distribution and ecology.—U.S.A.: Endemic California. Flowering Aug-
SQp.Hosis:mos[]y Eryngiuniaristulatum,EA^ascyi,Exastrcnsc,E.ahsn]acJoliu^^
and minima^ on Polygonum
Navarretia leucocephala, N. but also keUoggii,
pygmacum; margins
Epilobiuni of vernal pools.
G2G3
Conservation status— (imperiled to vulnerable) (G3, NatureServe
2005).
The The becomes
biology of this species deserves future study. parasite
C
strictly localized to the inflorescence region of the host. Flowers of howclliana
develop inside the dense host inflorescences and apparently synchronize their
The
anthesis with that of the host's flow^ers. parasite achieves both protection
and proximity the flux of assimilates intended the development hosts
to tor ol
reproductive structures.
Durand
3. Cuscuta subinclusa &r Hilgard, Acad. Nat. Sci. Philad. ser. 2, 3:42.
J.
1855. Typh: U.S.A. CAi-irORNiA. [Los Angeles Tcjon Pass, on a willow, Hccnnann (liO-
Co.]: s.n.
PH
LOTVPH: presuniabl); fragment MO).
Cuscuta ceanothi Bohr. Proc. Calif. Acad, (ccl 2) 1:16, 1854. The protologuc gave no information
anda
regarding a r\'pe. neocypiiication probal:>ly will be required tofirmly esrablish the iden-
name comments name
tity of this (sec above). Cuscuta ccanolhi the earlier but tenta-
is is
C
tively placed here with subinclusa.
Stems medium, sometimes fleshy, creamy. Inflorescences few- to several-flow-
m mm
ered, scattered to densely aggregated clusters; pedicels 0-1 long; bracts
mm)
1-0, ovate to lanceolate. Flowers 5-merous, 5-7(-9 long, white. Papillae
present in the corolla lobes; laticifers isolated or in row^s obvious in the calyx,
and
corolla fruit. Calyx campanulate, ca. 1/2 as long as the corolla tube, divided
3/5-2/3 the length, lobes broadly ovate to lanceolate, acute, sometnnes cuspi-
mm
date, basally overlapping. Corolla tube cylindric, 2.5-3.5(-4.5) long, usu-
when
ally showing horizontal ridges betw^een the stamen attachments dry, lobes
and
ovate-triangular, acute often slightly acuminate, 1/4-1/3 as long as the tube,
mm;
widely spreading to rellexed. Stamens subincluded; anthers linear 0.8-2
mm.
filaments 0-0.1 Pollen 3(-4)-zonocolpate (15-)17-22(-24) long, poly-
|.im
morph, subsphaerical to subprolate, rounded at poles, tectum microreticulate,