A NEW SPECIES OF HESPEROLINON (LINACEAE) FROM HUNTING CREEK IN NAPA COUNTY, CALIFORNIA

2006·3.6 MB·English

by  Richard O'donnell

Madrono, Vol. 53, No. 4, pp. 404^08, 2006
A NEW SPECIES OF HESPEROLINON(LINACEAE) FROM HUNTING CREEK IN
NAPA COUNTY, CALIFORNIA
Richard O'Donnell
CA
1317 Cornell Avenue, Berkeley, 94702
[email protected]
Abstract
A new species ofHesperolinon is described that is distinguished by its morphology, particularly its
three carpels and styles, dichasial inflorescence, and certain petal characteristics. It is a serpentine
endemic and may be related to Hesperolinon bicarpellatum.
Key Words: Hesperolinon, serpentine endemism, new species, Helen Sharsmith.
Species Treatment Napa County and the Sargent cypress forest on
the bluffs above Hunting Creek in Lake County.
Hesperolinonsharsmithiae Richard O'Donnell, sp. This area is in the southern Inner North Coast
nov.—TYPE: USA, California,mNapa Co., Range. At the type locality, H. sharsmithiae is
serpentine chaparral about 180 northwest associated with Cupressus sargentii Jepson, Arc-
of the junction of Cedar Creek and Hunting tostaphylos viscida C. Parry, Quercus durata
Creek, Paradise Valley, Napa County, Cali- Jepson, Streptanthus breweri hesperidis (Jepson)
fornia. About 122°24'W 38 47'N, about 270 m Jepson, Streptanthus glandulosus Hooker, Navar-
elevation. Richard O'Donnell s.n. (Holotype: retiajepsonii Jepson, Vulpia microstachys (Nutt.)
JEPS). Collected 6-9-2005. Bent., Cryptantha hispidula Brand, Allium fim-
Hesperolinon sharsmithiae, sp. nov. Herba annua, briatum S. Watson, and Alliumfcdcifolium Hook-
5-50 cm alta; Inflorescentia paniculata cymulis er and Arnold. It is named to honor Helen
Sharsmith whose major contribution to the
plerumque dichasialibus ramis secundariis op-
knowledge of Hesperolinon morphology and
posites; Sepalis binis exterioribus et ternis
ecology has not been equaled.
interioribus minoribus vex porrectis; Petalis
mm mm
3^.5 longis, 2-2.5 latis, luteis; Fila-
mm mm
mentis 1.5-2.5 longis, antheris 1-1.5 Discussion
longis; Ovario 3 - carpellato, stylis 3, 2-
3.5 mm longis. Hesperolinon sharsmithiae superficially resem-
bles three other Hesperolinon species: Hesperoli-
Annual; Stem 5-50mcmm tall; Leavemsmlinear, non clevelandii (Greene) Small, H. tehamense H.
narrow at base, 15-20 long, 1-1.5 wide, Sharsmith, and H. bicarpellatum H. Sharsmith.
stipular glands present; Inflorescence dichasial All have yellow flowers, linear, non-clasping
cyme, primary branches alternate, spreading, cauline leaves, and a diffuse inflorescence. Ta-
secondary branches equal and opposite, dichot- ble 1 compares the morphology of H. shars-
omous; Flowers scattered, the ultimate branchlets mithiae, H. clevelcmdii, H. bicarpellatum, and H.
mm
bearing 1 or 2 flowers; Pedicmelms 0.5-2 long tehamense. In addition to the traditional mor-
near tips of branches, 4 5 long on lower phological features, the comparison includes the
axils; Sepals 5, equal, sparsely glandular on description of a floral structure that surrounds
mm
margins, 3 long, oblanceolate, the two outer the base of the ovary that is called the "cup",
sepals and three inner sepals, connivent in bud; illustrated in Fig. 2. (In Linaceae, the staminal
Petals oblanceolate to obovate, almost oval, filaments are basally fused to form a cup that
mm mm
erose, 3-4.5 long, 2-2.5 wide, yellow, surrounds the base ofthe ovary.) The five petals
sometimes red along midvein or elsewhere, of Hesperolinon species attach at the rim of the
attached to the rim of the cup; Cup yellow; cup, alternating with the filaments, but unlike the
mm
Stamens yellow, filaments 1.5-2.5 long, each filaments, they are attached very lightly and are
filament iscontinuous with the rim ofthecup and easily detached. The rim of the cup is lobed
at its base, each filament has a pair of short, between the alternating filament/petal attach-
narrow lobes on either side; anthers, yellow, 1- ments. The comparison also includes the base of
mm
1.5 long, pollen grains yellow; Ovary 3- the petals and the petal base appendages. For
mm
carpellate, ovules 6, styles 3, 2-3.5 long; Fruit example, the petal appendages in H. clevelandii
mm
globose capsule about 2 long and as wide. are either poorly developed or absent, while they
Hesperolinon sharsmithiae is abundant in the are well developed in H. sharsmithiae and H.
serpentine chaparral along Hunting Creek in bicarpellatum.
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MADRONO
406 [Vol. 53
Comparative Morphology similarities between those specimens and H.
sharsmithiae.
No genetic analyses ofthe HesperoUnon species The Jepson Herbarium houses five specimens
have been published. Notwithstanding the lack of labeled HesperoUnon serpentinum. Two of the
this valuable data, comparative morphology is specimens (Taylor 14933, 14952) are from Sta-
sufficient to establish the distinctiveness of H. nislaus County and generally resemble H. shars-
sharsmithiae. Table 1 compares the morphology mithiae, except that the inflorescence bracts ofthe
of H. sharsmithiae with the morphology of the former are single and very narrow, while those of
three similar yellow-flowered HesperoUnon spe- the latter are opposite and wider. Other speci-
cies that grow in the vicinity. mens (Taylor 16669 - multiple plants) were
I have omitted from the comparison H. collected near Butts Canyon in Lake County.
serpentinum McCarten, a taxon that was first They appearto be H. bicarpeUatum displayingthe
referred to in the Jepson Manual (Hickman intermediate tricarpellate character discussed
1993), because it was not accompanied by above. The characters ofthe remaining specimen,
a formal description and a type specimen was collected by Jepson and later labeled HesperoU-
not designated for it, and thus the name is non serpentinum, are too indistinct to determine
effectively illegitimate. However, I examined the species. Jepson collected it at a place called
specimens at the Jepson Herbarium that are "La Brusca" on Howell Mountain in Napa
labeled HesperoUnon serpentinum and found County. The soil at La Brusca is volcanic; H.
2006] O'DONNELL: A NEW SPECIES OF HESPEROLINON 407
Hesperolinon sp. nov. by Richard O'Donnell, drawn by L.A. Vorobik
Fig. 2. Hesperolinonsharsmithiae. A. Typicalhabit, fairlydense,diffuseinflorescence. B. Habitsimplifiedtomore
clearlydepictthestrictlydichotomousbranching. C. Caulinepuberulenceconfinedasusualtotheinternodesabove
the leafaxils. D. Buds and partly open flower. E. Open flower with three exserted styles. F. Cross section ofcalyx
illustrating placement of cup. Note sparse glandulosity on sepal margins. G. Cup with filaments and petals
attached. H. Petal base. I. Fruit.
—
. .
MADRONO
408 [Vol. 53
styles and the latter two. However, some
individuals and populations of H. bicarpellatum
just southeast of Butts Canyon display a partial
tricarpellary condition.
TheextensivepopulationsofH. bicarpellatumin
Butts Canyon (Fig. 1) are uniformly bicarpellate.
Fig. 3. Petal bases: A. Hesperolinon sharsmithiae, B. Plants bearing both bicarpellate and tricarpellate
H. bicarpellatum, C. H. clevelandii, D. H. tehamense. flowers begin to occur on the ridge between Butts
The illustration of H. sharsmithiae and bicarpellatum Canyonand PopeValley(pers. obs.)andcontinue
are from fresh specimens. The lateral appendages ofH. to occur to the southern end of its known
sharsmithiae and H. bicarpellatum are frequently more distribution in Steele Canyon. Sharsmith (1961)
alike than depicted. H. clevelandii and tehamense are observed this phenomenon and described the
based on illustrations in Sharsmith. tricarpellary condition as "intermediate" and
"...never completely 3-carpellary". Specifically,
serpentinum is reported only from serpentine soils she reports a maximum of 50% tricarpellary
while H. clevelandii is found on both serpentine flowers on individuals ofH. bicarpellatum.
and volcanic soils. Thus, this specimen is more I sampled individual plants from four popula-
likely to be H. clevelandii than H. sharsmithiae. tions on the ridge between Butts Canyon and
Hesperolinon sharsmithiae and the invalid "ser- Pope Valley (Fig. 1), in the vicinity ofa site that I
pentinum" may be the same entity but the had sampled in previous years and found to be
material housed at the Jepson Herbarium does intermediates. I examined 14 plants, dissected all
not provide material support for that position. of the open flowers, nearly open buds, and very
The California Academy of Sciences herbarium young buds of each plant and f—ound that 330
has no specimens that are labeled H. serpentinum. buds out of 339 buds examined over 97%
I also examined specimens of H. tehamense at were tricarpellate. This is a much higher pro-
the California Academy of Sciences herbarium portion of tricarpellate flowers than Sharsmith
ananrdroawtlythediJsetprisbounteHderibnarTieumh.amTahisansdpecGilesenins oibnsteerrvmeedd.iatAeltchhoaurgachteIrsdiidn ntohetseobpsoepruvleatiootnhse,r
Counties. Its floral parts are generally larger than additional studies of the populations in this area
those of H. sharsmithi—ae and it is frequently and annual monitoring may reveal other in-
pubescent throughout a light—vestiture that termediate characters and help to clarify the
gives it a hoary appearance which H. relationship of these intermediate populations to
sharsmithiae lacks; H. sharsmithiae is glabrous, populations ofHesperolinon sharsmithiae and H.
except atthenodes. In addition, thecupandpetal bicarpellatum. I have found no bicarpellary
appendages of H. sharsmithiae differ from those flowers among the extensive Hunting Creek
ofH. tehamense as shown in Fig. 1 populations ofH. sharsmithiae.
The descriptions ofthe three species compared
to H. sharsmithiae in Table 1 are abbreviated
versions ofSharsmith's very detailed descriptions Conclusion
(Sharsmith 1961). They do not always agree with
the details in the descriptions in The Jepson Hesperolinon sharsmithiae is a new species that
Manual (Hickman 1993) or Munz and Keck differs from H. bicarpellatum in style number,
(1959, 1968) but the differences are not material. number of carpels and ovules, and petal size; it
differs from H. tehamense in petal size, vestiture,
Relationshipto Hesperolinon length ofpedicel; it differs from H. clevelandii in
BiCARPELLATUM the development of petal appendages, petal size,
Hesperolinon sharsmithiae may be closely re- and edaphic preference. It most closely resembles
lated to H. bicarpellatum, with which it shares and may be related to H. bicarpellatum.
diagnostic characters as shown in Table 1 Literature Cited
Their known ranges overlap northeast of
Middletown but otherwise differ (Fig. 1). Hesper- Hickman, J. C. 1993. The Jepson Manual. Higher
olinon bicarpellatum flourishes in and around plantsofCalifornia. UniversityofCalifornia Press,
Butts Canyon, southeast ofMiddletown. Hesper- Berkeley, CA.
olinon sharsmithiae is abundant on both sides of Munz, P. A. and D. D. Keck. 1959, 1968. A
Hunting Creek south of Paradise Valley, partic- California Flora with Supplement. University of
ularly in an area called The Cedars, northeast of SharCsamliiftohr,niHa.PrKe.ss.19B4e5r.keAleny,ewCAsp.ecies ofLinum from
Middletown. Butts Canyon and the Cedars are the Coast Ranges of California. Madrono 8:
separated by the largely volcanic blue oak 143-144.
savannah ofGuenoc. . 1961. The genus Hesperolinon (Linaceae).
The number of styles is the primary distin- University of California Publications in Botany
guishing field character: the former has three 32.