Malva rotundifolia
 
Round-Leaved Mallow

Leaf Top

Regina
02-September-2015

M. rotundifolia is similar to M. parviflora.  I have identified this plant as R. rotundifolia because the carpel margins are angled but not winged, because the carpel margins are not toothed, and because the distal surfaces of the carpels do not have clear transverse ridges or net veins.  In addition, the calyx lobes are triangular and incurved at maturity.  Finally, the lower parts of the petals are hairy-margined. Note that Flora of the Great Plains states that the number of carpels for M. rotundifolia is 8-13, commonly 10.

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Rotundifolia: Answers to key questions in Budd's Flora (BF) and Flora of Alberta (FOA) leading to this species. These also include answers separating M. rotundifolia from M. parviflora in Flora of the Great Plains (FOGP).
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annuals; NOT [perennials] (BF)

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stems decumbent or ascending; NOT [stems erect] (FOA)

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stems generally much shorter; NOT [stems 1-2 m tall] (FOA)

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calyx incurved at maturity; NOT [calyx reflexed at maturity] (BF)

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calyx lobes narrowly triangular to triangular; NOT [calyx lobes broadly ovate, mucronate] (FOGP)

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petals scarcely longer than sepals; NOT [petals about twice as long as sepals] (BF)

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petals mostly 1 cm long or less; NOT [petals mostly 2 cm long or more] (FOA)

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petals 4-15 mm long; NOT [petals 15-35 mm long] (BF)

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petals white or pale purple; NOT [petals deep bluish-purple] (FOA)

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lower parts of petals hairy-margined; NOT [lower part of petals hairless] (BF)

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12-15 carpels; NOT [8-12 carpels] (BF)

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carpels sharply angled but not winged; NOT [carpel angles somewhat wavy-winged and denticulate] (FOGP)

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carpels with smooth backs; NOT [carpels with net-like venation on backs] (BF)

 

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Malva: Answers to key questions in Budd's Flora and Flora of Alberta leading to this genus. 
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leaves more or less lobed, but not divided; NOT [leaves palmately divided into 5 lobes, these entire or divided]

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flowers in axillary clusters or solitary; NOT [flowers in axillary racemes]

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calyx bractlets present; NOT [calyx bractlets absent]

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flowers not yellow

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stigmas extending along the inner surface of the filiform style branches; NOT [stigmas terminal, capitate]

 

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Malvaceae: Answers to key questions in Budd's Flora  leading to this family. 
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herbs; NOT [shrubs or trees]

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plants terrestrial or semiaquatic; NOT [plants aquatic, leaves submerged or floating]

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plants not with colored milky juice

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plants with more than one normal leaf

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some or all leaves alternate; NOT [leaves opposite, whorled, or basal]

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leaves with stipules; NOT [leaves without stipules, or having glands]

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leaves palmately veined

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flowers with two floral rings

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calyx regular; NOT [calyx irregular, some sepals smaller than others]

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each petal distinct from the others

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stamens numerous, united into a column; NOT [stamens usually separate or partly so, not in a column]