| Shrub to 1.5–2 m across and 1.5 m tall | Low spreading to 0.5(1) m tall and 2–3 m across |
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| Plants taller,shrub-like,not low spreading | Plants shorter,horizontally spreading,sometimes prostrate |
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| Cladodes wider,mostly ± 18 cm wide and ± 27 cm long | Cladodes narrower,mostly ±13 wide and 22–27 cm long |
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| Cladodes broadly obovate,oval,or subcircular,never narrow. | Cladodes obovate,rarely broadly obovate,manifestly tapering to |
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| Cladodes not noticeably tapering to the base,never forming | the base sometimes forming a neck |
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| a neck |
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| Areoles 3–4 in a diagonal line on cladode surface | Areoles 4–5 in a diagonal line on cladode surface |
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| Areoles slightly raised when new | Areoles always flat |
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| Vasculature between areoles may be visible and somewhat | Vasculature not elevated |
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| elevated as raised lines on new cladodes |
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| Glochids yellow or golden brown,not in an adaxial tuft | Glochids initially brownish-yellow in an adaxial tuft |
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| Glochids in areoles on face of pads longest in semicircle or cluster | Glochids in areoles on face of pads initially in small,tight,fairly |
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| near upper edge of areole with some scattered throughout the | even tuft above center of areole,becoming scattered sparsely |
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| areole from the beginning | throughout the areole only uncommonly after several years |
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| Zero to 2(3) spines,erect,semi-erect,or one occasionally deflexed, | Zero to 2 spines,sometimes one reflexed,plants sometimes |
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| plants appearing moderately spiny | appearing essentially spineless |
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| Flowers 9–10 cm across | Flowers to 8–9 cm across |
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| Flowers all yellow | Flowers all yellow or red and yellow |
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| Filaments yellow | If flowers red and yellow,filaments may be tinted pink |
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| Style greenish-white at anthesis | Style white at anthesis |
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| Cylindrical style | Bulbous style |
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| Stigma pale yellow to pale yellowish-green | Stigma white |
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| Pericarpel not elongate,± 3 cm | Pericarpel elongate, 4–6 cm |
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| Fruit egg-shaped or short pyriform | Fruit pyriform to clavate |
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| Seeds modestly reniform,margin thickish | Seeds subcircular,margin thin |
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| Seeds overall flat and thin | Seeds thickish |
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