Cypripedium arietinum
 
Ram's-Head Lady's-Slipper

Single Plant With Ruler

Eastern Saskatchewan
15-June-2009

Note that the remains of the previous year's capsule can be seen in this photo.

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Arietinum: Answers to key questions in Lilies, Irises & Orchids of Saskatchewan by Vernon L. Harms and Anna L. Leighton leading to this species. The answers are in the order you would normally work through the key.
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Lateral sepals separate, somewhat spreading; lip irregularly triangular in side view with a cone-like, downward-projecting tip; NOT [Lateral sepals united for nearly their full length (may be separate to near the base in C. passerinum); lip obovoid to +/- spherical, sac-like, the tip rounded, not cone-like or projecting downwards]

 

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Cypripedium: Answers to key questions in Lilies, Irises & Orchids of Saskatchewan by Vernon L. Harms and Anna L. Leighton leading to this genus. The answers are in the order you would normally work through the key. 
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Plants green, with at least some green leaf-blades, these sometimes early withering or late developing; flowering stems green (pale pink to purplish-red in Calypso bulbosa), bearing sheathing bracts in some species; rootstocks not coral-like; capsules spreading to erect (occasionally drooping when old); NOT [Plants non-green saprophytes lacking leaf-blades; flowering stems yellowish to purplish-red or brown (pale greenish-yellow in C. trifid), bearing sheathing bracts; rhizomes rootless, coral-like in their branching; capsules drooping]

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Flowers 1 to 2 per stalk (occasionally more in Cypripedium reginae and C. montanum), large, showy; lip 1 cm long or longer, either inflated or broad and flat; NOT [Flowers 3 or more in a spike-like inflorescence, small, often inconspicuous; lip usually less than 1 cm long, but if longer, neither inflated nor broad and flat]

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Lip inflated, a slipper-like or sac-like pouch; flower subtended by a single, large, usually leaf-shaped floral bract; leaves usually 2 or more, present at flowering-time, (in Calypso bulbosa the broad, basal leaf that is produced the previous fall, may or may not be present at flowering time); NOT [Lip broad and flat, not inflated; flower subtended by a pair of minute, scale-like floral bracts; leaf single, emerging during or after flowering from upper sheathing bract on stem, linear, grass-like, 2-4 mm wide, folded lengthwise]

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Leaves 2 or more, cauline or basal, lacking stalk-like bases, often folded lengthwise; lip an inflated, nearly closed, sac-like pouch, lacking an apron-like lamina; petal-like staminode present above stigma; stems arising from rhizomes with slender roots; NOT [Leaf, when present, single, basal, narrowed to a stalk-like base, not folded lengthwise; lip slipper-like with a large opening and a broad "toe" covered with a whitish, apron-like lamina; staminode absent; stems arising from bulbous corms]

 

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Orchidaceae: Answers to key questions in Budd's Flora leading to this family. 
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plants NOT aquatic

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flowers irregular; NOT [flowers regular]

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perianth present, conspicuous, in two series of 3 segments, often brightly colored; NOT [perianth absent or inconspicuous]

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perianth usually large, consisting of sepals and petals usually alike, variously colored; NOT [perianth small, consisting of 3 green sepals and 3 whitish petals]

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petals NOT deciduous

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stamens 1 or 2; NOT [stamens 3 or 6]