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Vascular Plants of California
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Mammillaria dioica

Higher Taxonomy
Family: CactaceaeView DescriptionDichotomous Key
Habit: Perennial herb, shrub, tree, generally fleshy. Stem: cylindric to spheric, or flat; surface smooth, tubercled, or ribbed (grooved); nodal areoles bearing flowers. Leaf: generally 0 or early-deciduous, flat to +- cylindric. Spines: areoles generally with central, radial spines, occasionally with glochids. Flower: generally 1 per areole, bisexual [unisexual], sessile, radial [bilateral]; perianth parts generally many [5], scale-like to petal-like; stamens many; ovary inferior [superior], style 1, stigma lobes generally several [many]. Fruit: dry to fleshy or juicy, indehiscent to variously dehiscent, spiny, scaly, or naked; tubercled or smooth. Seed: generally many, occasionally 0--few.
Genera In Family: +- 125 genera, +- 1800 species: America (especially deserts), Africa; many cultivated, some edible. Note: Spines smaller, fewer (0) in shade forms; yellow spines blacken in age. Introduced species increasingly escape cultivation. Hybridization common in some genera.
eFlora Treatment Author: Bruce D. Parfitt, except as noted
Scientific Editor: Bruce D. Parfitt, Douglas H. Goldman, Bruce G. Baldwin, Thomas J. Rosatti.
Genus: MammillariaView DescriptionDichotomous Key

Habit: Generally erect (decumbent or prostrate), branched or not, branches 0--9(50). Stem: 5--30 cm, [1.8]3--7.5[20] cm diam, spheric to cylindric [or obconic], firm to soft, not regularly segmented; ribs 0, tubercles prominent, conic to cylindric, not grooved. Spines: [2]14--64(90) per areole, < 2 mm diam, needle-like [to hair-like or bristle-like], glabrous [or plumose], straight or hooked [or curved to crinkly]; central spines 1--4 [0--many] per areole, generally hooked. Flower: lateral, in axils of tubercles, 1--5 [7.5] cm diam; perianth cream to white, pink, purple, or lavender; ovary glabrous, spines 0, scales 0. Fruit: club-shaped or cylindric to ovoid [or barrel-shaped], indehiscent, generally red, spines 0. Seed: 0.8--1.5 mm, generally shiny, generally pitted or raised-netted, black [brown to +- red or +- yellow], occasionally with aril.
Etymology: (Latin: nipple)
eFlora Treatment Author: Bruce D. Parfitt
Reference: Hunt 1984 Bradleya 2:65--96; Hunt 1985 Bradleya 3:53--66; Hunt 1987 Bradleya 5:17--48
Mammillaria dioica K. Brandegee
Habit: Plant with flowers generally either all bisexual or all pistillate. Stem: generally 1(many), 5--30 cm, 3--7 cm diam, spheric to long-cylindric, firm; tubercle axils bristly. Spines: central spines 1--4 per areole, 8--15 mm, 1 hooked; radial spines 11--22, 4--10 mm. Flower: 10--22 mm, 20--40 mm diam; outer perianth parts entire to minutely fringed; inner perianth parts 8--12. Fruit: 10--25 mm, in age ovoid to club-shaped. Seed: aril 0. Chromosomes: 2n=[44]66.
Ecology: Hillsides, washes, coastal scrub to creosote-bush scrub; Elevation: 10--1500 m. Bioregional Distribution: SCo, w edge DSon; Distribution Outside California: Baja California. Flowering Time: Feb--Apr
Synonyms: Mammillaria dioica var. incerta (Parish) Munz
Jepson eFlora Author: Bruce D. Parfitt
Reference: Hunt 1984 Bradleya 2:65--96; Hunt 1985 Bradleya 3:53--66; Hunt 1987 Bradleya 5:17--48
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

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Botanical illustration including Mammillaria dioica

botanical illustration including Mammillaria dioica

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Citation for this treatment: Bruce D. Parfitt 2012, Mammillaria dioica, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on February 29, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora,, accessed on February 29, 2024.

Mammillaria dioica
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©2009 Barry Breckling
Mammillaria dioica
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©2012 Keir Morse
Mammillaria dioica
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©2009 California Academy of Sciences
Mammillaria dioica
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©2012 Keir Morse
Mammillaria dioica
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©2015 Barry Rice

More photos of Mammillaria dioica
in CalPhotos

Geographic subdivisions for Mammillaria dioica:
SCo, w edge DSon
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).


Data provided by the participants of the  Consortium of California Herbaria.
View all CCH records
All markers link to CCH specimen records. The original determination is shown in the popup window.
Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.

CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).