Morin, sp. nov.The species is named ofor Helen K. Sharsmith in recognition of her extensive work in the Mt. Hamilton Range and of her many careful collections and observations of Campanulaceae in California.1) Species haec ab Campanula exigua differt foliis crassiusculis lanceolato-ovatis, bracteis oppositis; supernum dimidium pilis rigidis, verrucosis, 0.1-0.2mm x 0.2-0.4mm.
All of the California annuals (Campanula angustiflora, Campanula exigua, Campanula sharsmithiae and Campanula griffinii) have been a source of confusion since their discovery, judging from the misidentifications found in herbaria, and they are not known to be closely related to any other campanulas. Treatment of small-flowered and annual Old World campanulas has been controversial (Boissier, 1874; de Candolle, 1830; Gadella, 1964, 1966; Federov, 1957), and knowledge of New World campanulas is very limited (Shetler, 1963). Here I give detailed descriptions of the Californian annual campanulas in order to facilitate eventual comparison between them and their Nort American relatives and between them and their Mediterranean counterparts.2)
W.H. Brewer (1867) made the earliest known collection of this group in 1862 on Mt. Hamilton (Santa Clara Co.) just a few days after he had found its striking associate, Clarkia breweri (A. Gray) Greene. Gray never assigned a species name to the specimen, and this campanula was not collected again until Rattan found it on Mt. Diablo (Contra Costa Co.) and described it as Campanula exigua (Rattan, 1886). In his description, Rattan referred to a plant taken that same year by Mrs. Curran on Mt. Tamalpais (Marin Co.). Alice Eastwood (1898) included the Mt. Tamalpais plant in Campanula angustiflora Eastwood. In her discussion of the new species, Eastwood referred to “very young specimens of an annual Campanula” collected in Priest Valley (Monterey Co.) that shared some characteristics with both named taxa, but that she chose to retain in Campanula angustiflora. Howell (1938) eventually described this plant as Campanula angustiflora var. exilis, herein named Campanula griffinii.3)
Erect annuals, 5-25cm high; stems 4-angled, glabrous or hispid below first flower, the upper part usually with few to many broad, verrucose hairs that are 0.1-0.2mm wide, 0.2-0.4mm long.
Morphological simularities of these taxa to other Nort American Campanulideae may be due to convergence; consequently, the relationships of these four species (Campanula angustifloar, Campanula exigua, Campanula sharsmithiae and Campanula griffinii) are obscure.
Both Campanula exigua and Campanula griffinii have narrow, somewhat sclerophyllous leaves and bracts. The bracts in both species are arranged near the apex of each branch but at least 4mm and more often 7-8mm apart. Consequently, subsequent branches are arranged alternately. Because the flowers of Campanula exigua have long pedicels and the branches are widely spaced, the plants appear very open and delicate. In contrast, the bracts of Campanula sharsmithiae are opposite or nearly so and the branches, both of which usually develop, seem superficially to be truly dichotomous. The fleshy leaves are wider than those of Campanula exigua and the plants of Campanula sharsmithiae accordingly appear to be leafier and generally denser.
The indumentum of most California Campanuloideae is variable in its presence or absence and in its distribution on a plant. The hairs are usually of several lengths, all fairly long and narrow. To my knowledge, short, broad, verrucose hairs are not found in any other North American Campanuloideae. The combination of unique indumentum, fleshy leaves, broadly lanceolate, opposite, upper bracts, and many-pantoporate pollen seems sufficient for the recognition of this very restricted endemic.4)
Fleshy leaves and opposite bracts that are wider than those of Campanula exigua.Lower cauline leaves sessile, alternate, 5-11mm long, broadly spatulate, obtuse, few-toothed, abaxial side glabrous or hispid; upper cauline leaves fleshy, (5-)7-11mm long, broadly lanceolate, 3-5.5 times as long as broad, acute, with four pairs of long (0.9mm) teeth, abaxial side glabrous or hispid; longest leaf subtends first flower; upper bracts sessile, opposite to 3mm apart, 4-6mm long, broadly lanceolate (3-)4-5.5 times as long as broad.5)
Flowers May - Jun.The flower structure of Campanula exigua is typical of campanulas and in terms of flower morphology Campanula exigua and Campanula sharsmithae retain the most primitive characteristics of the annual species discussed here. Flowers terminal, pedicel short, straight, 1-3mm long; corolla (6.5-)8-16mm long, 2-3(-4) times as long as ovary, funnelform-campanulate, deep lavender; lobes 5, about 1/2 tot 1/3 the length of the corolla, twice as long as wide, acute; corolla papillate inetrnally at base and along sides beneath sinuses; style lobes 1.2mm long, tightly appressed at anthesis; stamens 4.5-5.3mm long, anthers nearly twice as long as filaments, filament abruptly dilated to a wide ciliate base.6)
Large corolla, pantoporate pollen. Pollen 14-20 pantoporatum, 0.035mm dia.; ovary 2-4.4mm long, 1.5-2(-2.5) times as long as wide, long-conical at base, cylindrical sides short, strongly ribbed, the inter-rib area not infolded or tuberculate.7) (Fig.2).
n = 17 8)
Capsule 4-6mm long, the pore about midway between base and apex; calyx lobes erect, subulate, 1-2 times as long as ovary and capsule; ovules 60-100, seeds 0.65-0.73mm long, oblong, elliptical in cross-section, about twice as long as broad, flat on chalazal end, light brown, shiny, finely striate.9)
Four of the ten species of Campanula that are found in the California Floristic Province are annuals; Campanula sharsmithiae - is restricted to steep serpentine talus slopes in the Mt. Hamilton Range.Type: CA: Stanislaus Co., Red Mountains, 27km (17mi) above mouth of Arroyo del Puerto, Mt. Hamilton Range, 420m, rocky, almost barren talus slope, associated with Clarkia breweri, 19 May 1935, C.W. and H.K. Sharsmith 3144 )Holotype: UC!; Isotypes: DS!, GH!, WS!).10)
Local populations on steep serpentine talus slopes on and adjacent to Red mauntain, Mt. Hamilton Range, 400-800m (Fig.4).
Type: CA: Stanislaus Co., Red Mountains, 27km (17mi) above mouth of Arroyo del Puerto, Mt. Hamilton Range, 420m, rocky, almost barren talus slope, associated with Clarkia breweri, 19 May 1935, C.W. and H.K. Sharsmith 3144 )Holotype: UC!; Isotypes: DS!, GH!, WS!).
Paratypes: CA: Santa Clara Co.: near headwaters of Colorado Creek, Red Mountains, Mt. Hamilton Range, 25 May 1935, C.W. and H.K. Sharsmith 3165; Blackbird Valley, s. of Mt. Mocho, with Streptanthus breweri, Eriogonum covillianum, and Clarkia breweri, 800m, 12 May 1980, Morin 301; Stanislaus Co., confluence of Arroyo del Puerto and Hideout Canyon, with Quercus durata, Streptanthus breweri, Eriogonum covillianum, 400m, 11 May 1980, Morin 299 (chromosome voucher). These are the only known collections of Campanula sharsmithiae.The slopes on which Campanula sharsmithiae is found are nearly devoid of soil or grass cover and are very unstable. Campanula exigua grows on more gradual slopes that have a sparse covering of grass and other small herbs.11)
Seeds of field-collected plants were grown at the University of California Botanical Garden in pots of “UC Mix, formula C” soil (Matkin and Chandler, 1957), in insect exclosures, for studies of morphology, cytology, and pollination system. Seed sources are indicated in the Taxonomic Treatment and included at least one northers and one southern population of each species except Campanula sharsmithiae, seeds of which were not available. Voucher specimens are in UC.
Buds from field-collected and garden-grown plants were preserved in Carnoy's 6:3:1 solution; microsporocytes were stained in acetocarmine for chromosome preparations. Pollen was mounted in lactophenol and cotton blue for study of general morphology and was prepared following the method of Lynch and Webster (1975) for study of exine ultrastructure, except that material was CO2-critical-point-dried directly from 100 percent ethanol. After initial preparation the pollen was coated with 30nm of gold palladium and viewed on a Coates and Welter Model 50 Emission Scanning Electron Microscope.
Measurements of vegetative and floral parts were made on pressed, garden-grown plants and on herbarium specimens from BR, CAS, CU, DAV, DS, GH, JEPS, K, MICH, MO, ND, NO, NY, ORE, OSC, PH, POM, RSA, SBBG, UC, UCSB, US, UTC, WS, and WTU. Corollas of living plants were photographed in direct sunlight with a Tiffin 18A Photar filter with high speed Ektachrome and Tri-X films to document ultraviolet (UV) absorptions patterns.
Flowers of carpellate parents in artificial crosses were emasculated before anthesis and later pollinated by transferring pollen from the style of the staminate parent, on sterile forceps, to the stigmatic surface of the carpellate parent. Except when they were being manipulated, the flowers were covered with Kimwipe bags before anthesis with no further treatment. Self-compatibility of Campanula exigua was tested by transferring pollen from the style to the stigma of the same flower. Pollen is deposited on the stigmatic area of Campanula angustiflora and Campanula griffinii before anthesis and therefore was not artificially transferred. Presence of apomixis was tested by leaving emasculated flowers unpollinated.
Results of methods
The two most obvious characters that separate these annual species are leaf width and corolla size (Figs. 1 and 2).
Campanula exigua and Campanula sharsmithiae have large flowers. The former has thin, narrow leaves and the latter has fleshy, broader leaves. Campanula griffinii has narrow leaves and small flowers, and Campanula angustiflora has broad leaves and small flowers. These species also differ in ovary shape, filaments shape, and position of upper bracts. These characters, along with flower size and leaf shape, are more constant under garden conditions than most other characters. For this reason, they were chosen as major, differentiating characters.
Campanula exigua, Campanula sharsmithiae and Campanula griffinii have n = 17, wheras Campanula angustiflora has n = 15; they are the first annual campanulas reported to have these numbers. At least two populations of each species (only one for Campanula sharsmithiae) were counted; vouchers are deposited in UC and indicated in the Taxonomic Treatment.
Campanula exigua has 12-pantoporate pollen, Campanula sharsmithiae has 14-20 pantoporate pollen, and Campanula griffinii has 8-pantoporate pollen (Fig.3). Pantoporate pollen in Campanulaceae has previously been known only from Campanula americana (Dunbar, 1975). Campanula angustiflora has 6-porate pollen, the pores equatorial (Fig.3). Following the terminology used by Dunbar (1975), pollen sexine fine structure for the species studied can be described as short ridges, tip end bent upwards, with basally divided spinules (Fig.3).
Reciprocal crosses among all species were unsuccessful. Unemasculated, bagged flowers and unbagged flowers of Campanula angustiflora and Campanula griffinii set seed (50-80 seeds per capsule), but emasculated, unpollinated flowers did not produce seed. These two species are self-pollinating and self-compatible; they do not appear to be apomictic, but pseudogamy cannot be ruled out. No flowers of Campanula exigua produced seed. Since even control, intrapopulational crosses were unsuccessful even though flowers in the field produce up to 100 seeds each, failure may have been due to technical problems such as mechanical damage to the stigma. Campanula exigua is not self-pollinating and seems to be self self-incompatible.