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Cruckshanksia Hook. & Arn. (Rubiaceae: Coussareae)
Charlotte M. Taylor [webpage]
Missouri Botanical Garden
P.O. Box 299
St. Louis, MO 63166
Click on the images below to see a larger image
Cruckshanksia hymenodon in northern Chile
Cruckshanksia pumila in the Atacama Desert of Chile
Cruckshanksia Hook. & Arn. includes seven species of low,
hemicryptophytic shrubs and annual herbs found in the Atacama Desert
and the Andes of nothern to central Chile and adjacent Argentina.
Cruckshanksia can be recognized by its opposite leaves, its
interpetiolar stipules that are triangular to bilobed or erose, its
flowers borne severally in terminal cymes, its yellow or pink
salverform corollas with slender long tubes, and its papery
loculicidal capsules. The flowers are diurnal and distylous. The
tissue do contain raphides, although these may be difficult to observe.
The leaves and inflorescence bracts of several species of
Cruckshanksia may be deeply 2-3-lobed. Several species have
one or more calyx lobes on each flower that are expanded into
calycophylls (i.e., expanded foliaceous structures), which are
petaloid and white to colored in flower and later become papery. In
flower these structures presumeably help attract pollinators, while
in fruit they apparently aid in dispersal or at least dehiscence of
the capsules. The annual species C. pumila grows in regions
of the Atacama Desert that only receive rain during El Niño
years, thus only for a couple weeks every third to fifth year; its
seeds are dormant on the ground between rains. Cruckshanksia
hymenodon is the most widely distributed and frequently collected
species of this genus.
Cruckshanksia has been confused with another genus of
southern South America, Oreopolus Schltdl. However these genera
differ in several characters, as summarized in the key presented on
the Oreopolus web page.
Cruckshanksia and its relationship to Oreopolus have
been studied by Ricardi (1963), Ricardi & Quezada (1963), and Taylor
(1996). Ricardi (1963) and Ricardi & Quezada (1963) recognized seven
species of Cruckshanksia and three of Oreopolus; however
Taylor (1996) recognized only seven species of Cruckshanksia,
including two of the species that Ricardi & Quezada included in
Cruckshanksia was previously included in the Hedyotideae
by many authors, although Bremekamp and later Anderson & Rova (1999)
placed it in the Cruckshanksieae. More recently, based on molecular
data Bremer & Manen (2000) transferred both Oreopolus and
Cruckshanksia to the neotropical tribe Coussareae. In their
expanded circumscription Coussareae comprises a notable range of fruit
types, from single- to multi-seeded, fleshy, indehiscent fruits
(Coussarea, Coccocypselum) to leathery schizocarps
(Declieuxia) and dry multi-seeded capsules
(Heterophyllaea); it is not yet clear what morphological
features unite the genera now placed in this tribe.
- Andersson, L. & J.H.E. Rova. 1999. The rps16 intron and
the phylogeny of the Ruboideae (Rubiaceae). Pl. Syst. Evol. 214:
- Bacigalupo, N.M. 1999. Rubiaceae. In: M. N. Correa, Flora
Patagonica Parte 6: 423-443.
- Bremer, B. & J.-F. Manen. 2000. Phylogeny and classification of
the subfamily Rubioideae (Rubiaceae). Pl. Syst. Evol. 225: 43-72.
- Moore, D.M. 1983. Flora of Tierra del Fuego.
- Ricardi, M. 1963. Rehabilitación del género
Oreopolus Schlecht. Gayana, Bot. 7: 3-7.
- Ricardi, M. & M. Quezada. 1963. El género
Cruckshanksia (Rubiaceae). Gayana, Bot. 9: 3-36.
- Taylor, C.M. 1996. Taxonomic revision of Cruckshanksia
and Oreopolus (Rubiaceae: Hedyotideae). Ann. Missouri Bot.
Gard. 83: 461-479.
Key to the Species of Cruckshanksia
- 1. Calyx lobes equal, none bearing petaloid appendages or
all the lobes
- bearing them, thecalyx lobes elliptic to oblanceolate or
with stipitate, elliptic to ovate petaloid appendages (i.e.,
calycophylls) in flower, these appendages sometimes becoming
orbicular to broadly elliptic in fruit.
- 2. Leaf blades 15-40 mm long, sharply acute at apex; stipules
- long; calyx lobes in flower 10-15 mm long, in fruit 12-23 mm
long, without stipes...C. palmae
- 2. Leaf blades 8-20 mm long, obtuse to rounded at apex; stipules
- 0.8-1.6 mm long; calyx lobes in flower 3.5-11 mm long (including
stipe, when present), in fruit 7-17 mm long, elliptic to oblanceolate,
and without stipes, or 10-15 mm long and with stipes.
- 3. Calyx lobes in flower all composed of stipes 3-6 mm long bearing
- elliptic to ovate appendages 3-5 mm long, in
fruit the stipes 10-15 mm long with the appendages ovate and
9-13 mm long....C. lithiophila
- 3. Calyx lobes elliptic to oblanceolate, without stipes, in
- 3.5-5 mm long, in fruit 7-17 mm long...C. macrantha
- 1. Calyx lobes unequal with 1-4 of them bearing petaloid
- appendages orbicular to broadly elliptic in flower and fruit,
the remaining 1-4 calyx lobes elliptic to narrowly triangular or
- 4. Plants annual or perhaps sometimes perennial; corolla lobes
- long; corolla tube 0.1-0.3 mm in diameter near its middle...
- C. pumila
- 4. Plants perennial; corolla lobes 2-4.5 mm long; corolla
tube 0.3-1 mm
- in diameter near its middle.
- 5. Petaloid calyx lobe appendages pink or white (though
- drying yellow); leaves 2-15 mm wide...C. hymenodon
- 5. Petaloid calyx lobe appendages yellow; leaves 0.8-6 mm wide.
- 6. Cauline leaves simple or sometimes 3-lobed; petaloid calyx
- lobe appendages 6-10 x 8-15 mm in flower, to 12 x 18 mm in fruit...
- 6. Cauline leaves simple to usually 2-3-lobed; petaloid
- lobe appendages 3-6 x 2-7 mm in both flower and fruit.....C. verticillata
List of Names and Synonyms of Cruckshanksia
Accepted names are presented in bold; synonymous names
appear with an equals sign. Further information on these names
can be found in the TROPICOS database
Cruckshanksia bustillosii Phil. = Cruckshanksia hymenodon
Argentina, 20-2950 m
Cruckshanksia capitata Phil. = Cruckshanksia montiana
Cruckshanksia capitata var. densiflora (Phil.) Reiche = Cruckshanksia montiana
Cruckshanksia chrysantha Phil. = Cruckshanksia pumila
Cruckshanksia darapskyana Phil. = Cruckshanksia pumila
Cruckshanksia densifolia Phil. = Cruckshanksia montiana
Cruckshanksia geisseana Phil. = Cruckshanksia pumila
Cruckshanksia glacialis Poepp. & Endl. = Oreopolus glacialis
Cruckshanksia hymenodon Hook. & Arg., northern to central Chile and adjacent
Cruckshanksia hymenodon var. bustillosii (Phil.) Ricardi = Cruckshanksia
Cruckshanksia lithiophila Ricardi, Andes of northern Chile, 3300-3600 m
Cruckshanksia macrantha Phil., Andes of northern and central Chile and
Argentina, 1100-4300 m
Cruckshanksia montiana Clos, northern Chile, 10-500 m
Cruckshanksia palmae Clos, Andes of north-central Chile, 2000-4000 m
Cruckshanksia pumila Clos, northern Chile, 10-1900 m
Cruckshanksia tripartita Phil. = Cruckshanksia pumila
Cruckshanksia verticillata Phil., northern Chile, 100-1000 m
Oreopolus macrantha (Phil.) Ricardi = Cruckshanksia macrantha
Oreopolus palmae (Clos) Ricardi = Cruckshanksia palmae
Rotheria lanceolata Meyen = Cruckshanksia hymenodon
Text and Images, unless otherwise indicated, Copyright © by Charlotte M. Taylor. All rights reserved.
This page was revised on April, 2008.