Peritoma serrulata
Peritoma
guaco, guaco Rocky Mountain bee-plant, Rocky Mountain bee-plant, spider-flower, stinking bee-plant, stinking-clover, stinkweed
bee-plant, cleome, spiderflower
sparsely branched; glabrous or glabrate.
sparsely or profusely branched; glabrous, or glabrate, or glandular-pubescent.
(stipules bristlelike), petiole 1.5–3.5 cm;
leaflets 3, blade elliptic, 2–6 × 0.6–1.5 cm, margins entire, weakly sinuate, or serrulate, apex acute, long-acuminate, or mucronate, surfaces glabrate (margins with sparse, relatively long hairs when young).
stipules scalelike, bristlelike, or absent;
petiole with pulvinus basally or distally;
leaflets 3 or 5, (conduplicate and flat).
1–4 cm (4–30 cm in fruit);
bracts unifoliate, obovate, 4–22 mm.
terminal or axillary (from distal leaves), racemes (flat-topped or elongated);
bracts usually present.
(green to purple), 8–20 mm.
sepals persistent, connate 1/2–2/3 of length, purple to green, lanceolate, 1.7–4 × 1–2 mm, margins denticulate, glabrous;
petals purple (rarely white), oblong to ovate, 7–12 × 3–6 mm;
stamens purple, 18–24 mm;
anthers (green), 2–2.3 mm;
gynophore 1–15 mm in fruit;
ovary 5–7 mm;
style 0.1–0.5 mm.
zygomorphic;
sepals persistent or deciduous, distinct or partly connate (1/3–1/2 of lengths), equal (each often subtending a nectary);
petals equal;
stamens 6;
filaments inserted on cylindric androgynophore (usually expanded adaxially into a gibbous or flattened appendage), glabrous;
anthers (linear), coiling as pollen is released;
gynophore usually recurved in fruit (sometimes reflexed).
capsules (erect to pendent), dehiscent, usually oblong (obovoid, subglobose, or fusiform in P. arborea).
(erect) not inflated, 23–76 × 3–6(–7) mm, striate, (glabrous).
12–38, black, globose or horseshoe-shaped, 2.8–4 × 2.5–3 mm, rugose.
5–38, globose, obovoid, triangular, or horseshoe-shaped, not arillate, (cleft fused between ends).
= 10.
= 34, 60.
Peritoma serrulata
Peritoma
Most collections of Peritoma serrulata from the northeastern and midwestern United States apparently represent non-persistent waifs or garden escapes. The species has been cultivated as a source of nectar for honeybees since ca. 1880 (L. H. Bailey 1900–1902). It shows considerable variation in fruit size, even within populations. The variation may reflect environmental influences, especially water availability, rather than genetics (H. H. Iltis 1952).
The seeds and leaves of Peritoma serrulata are consumed by the Navajo as food and provide a source of black dye. The leaves have been used as a remedy for insect bites, inflammation, and intestinal upsets (L. S. M. Curtin 1947).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Species 6 (6 in the flora).
Whether included in Cleome or treated as a separate genus, Peritoma comprises mostly distinct, western North American species, perhaps related to African genera. It is best treated as a taxon equivalent in rank to its three derivative genera, Cleomella, Oxystylis, and Wislizenia (2n = 40). These can be arranged in a much studied fruit and seed reduction series correlated with increasing aridity (H. H. Iltis 1955, 1956, 1957; K. Bremer and H. Wanntorp 1978; S. Keller 1979; S. S. Vanderpool et al. 1991). Some botanists may object to inclusion of the well-established Isomeris arborea in Peritoma. It is the only long-lived woody shrub species in the North American Cleomaceae. Except for the larger size, the flowers are basically identical (as are the fruits and seeds) to those of species such as P. lutea, a fact appreciated long ago by E. L. Greene when that notorious splitter lumped Isomeris with its relatives in Cleome.
With six sharply distinct species (H. H. Iltis 1957), Peritoma is an exceptionally robust and relatively ancient genus, usually characterized by the rather thick trifoliolate and glabrous leaves, yellow (except a rich purple in P. multicaulis and P. serrulata) petals, and, usually, well-developed nectary discs.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Shrubs; capsules usually inflated, 6-12 mm diam. | P. arborea |
1. Annuals; capsules not inflated, 1.5-12 mm diam | → 2 |
2. Leaflets 5 (proximally) | → 3 |
2. Leaflets 3 (throughout) | → 4 |
3. Capsules 15-40 mm; gynophore 5-17 mm in fruit; petals light yellow, 5-8 mm; stamens 10-15 mm; plants (15-)25-30 cm. | P. lutea |
3. Capsules 40-60 mm; gynophore 15-25 mm in fruit; petals golden yellow, 10-13 mm; stamens 20-30 mm; plants 50-100(-200) cm. | P. jonesii |
4. Petals golden yellow; capsules pendent, glandular-pubescent. | P. platycarpa |
4. Petals purple, pink, rose, or white; capsules erect or reflexed, glabrous | → 5 |
5. Leaflets 0.6-1.5 cm wide; petioles 1.5-3.5 cm; petals 7-12 mm; capsules 23-76 mm. | P. serrulata |
5. Leaflets 0.1 cm wide; petioles 0.5-1.5 cm; petals 4-5 mm; capsules 15-25 mm. | P. multicaulis |
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CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
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WildflowerSearch
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- Local floras: CA, OR, WA
- Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria
- WildflowerSearch
- iNaturalist (observations)
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
