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campanula:americana

americana

Campanula americana

L.

Tall. B

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Habitus

Erect, simple or few-branched annual or biennial, to 6 ft., glabrous or pubescent.

Campanula americana flowering - Foto and drawing Herman Berteler
Campanula americana to run to seed - Foto and drawing Herman Berteler

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.

Leaves

Stem leaves lanceolate to ovate-elliptic, to 6 in. long, narrowed at both ends, serrate.

Campanula americana - Foto and drawing Herman Berteler

Flowers

Flowers 1-3 in the axils, in long spikes, calyx lobes linear, to ¾ in. long, corolla blue or white, to 1 in. across, rotate, style 3-lobed.

Pantoporate pollen in Campanulaceae has previously been known only from Campanula americana (Dunbar, 1975). 1)

Campanula americana - Foto and drawing Herman Berteler

Pollen

Most European Campanula pollen studied to date is 3- to 4-porate (Dunbar, 1975). Most North American campanulas (and other North American genera in Campanuloideae) have pollen that is 5- to 6-porate, the pores equatorial )Chapman, 1966; Chuang, pers. comm., 1978; Morin, unpubl. data). Only Campanula americana L., Campanula exgua, and Campanula griffinii are known to have pantoporate pollen, although pores of Campanula reverchonii are not strictly equatorial. Small (1903) placed Campanula americana in the monotypic genus Campanulastrum, and Gadella (1964) supported this decision. There is little morphological similarity between Campanula americana (which is a tall, broadleaved annual or biennial with spicate inflorescences and rotate corollas) and the annual California campanulas. Therefore it seems likely that pantoporate pollen evolved independently in these two groups.2)

Chromosomes

Only one other Campanula, Campanula americana, which is a virgate annual or biennial, is known to have pantporate pollen.3)

Fruit

Kapsel nahe der Spitze, seltener etwas oberhalb der Mitte sich offnend, 3facherig. Kelchbuchten ohne Anhangen. Sect. II Rapunculus Boiss.4)

Campanula americana - Foto and drawing Herman Berteler

Seed available, in small quantity. 5)

Living

Moist, shady places.

Origin

Eastern North America

1) , 2) , 3)
:ref:nancymorin01
4)
:ref:aengler01
5)
:ref:alpinaresearch03
campanula/americana.txt · Laatst gewijzigd: 2018/05/03 10:18 (Externe bewerking)