Plant Index


 
 
 

Houstonia caerulea

Houstonia caerulea L.

azure bluet, common bluet, innocence, quaker ladies

Synonym(s): Hedyotis caerulea, Houstonia caerulea var. faxonorum
Houstonia caerulea (Azure Bluet)
Image ID: 9148
Image by: Ware, Richard & Teresa
Image Collection: NCBG Digital Library

PLANT INDEX

ID_PLANT: HOCA4
SCIENTIFIC NAME: Houstonia caerulea
Include in WOTAS: 1
Publish to Web: 1
Last Modified: 2017-12-14

GENUS INDEX

GENUS CODE: HOUST
GENUS SCIENTIFIC: Houstonia
GENUS AUTHORITY: L.
GENUS COMMON: Bluet
GENUS SUMMARY: The generic limits of Houstonia, Hedyotis, Oldenlandia, and Stenaria have been controversial, with much shuffling of generic configuration. It now appears that Houstonia should be recognized as a genus separate from Hedyotis and Oldenlandia, with Stenaria included in Houstonia (Guo et al. 2013; Wikström et al. 2013, and other references).
GENUS IDENTIFICATION: Identification notes: In the key below, all leaf measurements and length/width ratios are based on median cauline leaves.
GENUS REFERENCES: Terrell (1959)=Z; Terrell (1991)=Y; Terrell (1996)=X; Rogers (1987)=Q; Ward (2004c)=V; Church & Taylor (2005); Church (2003); Turner (1995b)=U; Terrell (2001)=M; Rogers (2005); Terrell (2007); Guo et al. (2013); Wikström et al. (2013). Key adapted in part from the references.

FAMILY INDEX

FAMILY CODE: RUBIAC
FAMILY SCIENTIFIC: Rubiaceae
FAMILY AUTHORITY: A.L. de Jussieu 1789
FAMILY COMMON: Madder Family
FAMILY SUMMARY: A family of about 630-650 genera and 10,200-13,000 species, trees, shrubs, vines, and rarely herbs, cosmopolitan, but especially diverse in tropical and subtropical areas. Subfamily and tribe classification follows Bremer & Eriksson (2009).
FAMILY REFERENCE: Bremer & Eriksson (2009); Rogers (1987, 2005).

NCBG DESCRIPTIVES

INTRO: Tufted, erect perennial of forests, woodlands, openings, lawns and a wide variety of disturbed sites.
STEMS: Stems thin, sparingly branched, smooth.
LEAVES: Leaves mostly basal in rosettes, petioled, spoon- to oblong-lance-shaped, less than 1/2 in. long, smooth to slightly hairy; stem leaves narrower and mostly sessile.
INFLORESCENCE:
FLOWERS: Flowers solitary at stem tips or in upper axils, 1/4-3/4 in. wide, pale blue to violet with yellow center, consisting of a short corolla tube and 4 spreading, slightly pointed lobes.
FRUITS: Fruit a 2-celled, green, slightly compressed and round capsule.
COMMENTS:
HEIGHT: 2-6 in.

DURATION: Perennial
HABIT: Herb

LEAF ARRANGEMENT: Opposite
LEAF COMPLEXITY: Simple
LEAF RETENTION:

FLORAL CHARACTERISTICS
SYMMETRY: Radial (Actinomorphic)
BLOOM TIME: (Late Jan-) Apr-Jul
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
x x x x x

BLOOM COLOR: Pale blue
White Red Pink Orange Yellow Green Blue Lavender Purple Violet Brown Not Applicable
x x

FRUITING PERIOD: May-Aug.

DISTRIBUTION
HABITAT TYPE: Disturbed, Moist forests, Woods margins
NATIVE RANGE: eastern North America

HORTICULTURAL
Plant Sale Text: Bluets are a diminutive and well loved wildflower, found from the edges of high mountain paths all the way to the lawns and meadows of the piedmont and coast. The tiny blue flowers are a sure sign that summer is on its way. Clump several plants together in a well protected spot such as the edge of a woodland path or a niche in some small rocky spot of your garden. Bluets dislike competition, but they are tough and will reward you with clumps of rosettes covered in a blue haze if given the proper space.

Bloom Table Text:

NCBG Location:

Cultural Notes:

SOIL MOISTURE: Dry, Average, Moist/Wet
LIGHT EXPOSURE: Sun, Part Shade, Shade
MINIMUM HARDINESS ZONE: 3
MAXIMUM HARDINESS ZONE: 9
GERMINATION CODE:
WILDLIFE VALUE: Bee Friendly
DEER RESISTANCE:

GRIM ACCESSIONS

acc_id acc_num acc_dt coll_id Action
234 2011-0062 2011-04-05 233 View
403 2015-0049 2020-01-27 233 View
2186 1986-1998 View
3259 1990-0109 View
4277 1992-0433 View
4953 1995-0071 View
5134 1995-0253 View
5838 1995-0966 View
6132 1995-1263 View
9218 2006-0114 2020-05-07 1292 View
9394 2021-0022 2021-03-18 0 View


GRIM COLLECTIONS

Coll_id Project Collection date Collector Action
233 HORT 2009-06-01 Poythress View
1292 HORT 2006-06-13 Bryan View


GRIM PLANTINGS

plt_num acc_id loc_num pers_num inst_dt Action
509 234 24 Heiney 2011-03-29 View
510 234 16 Liloia 2012-03-21 View
949 233 17 Liloia 2015-01-22 View
3777 2186 74 NCBG staff 1986-12-23 View
5430 3259 8 NCBG staff 0000-00-00 View
6605 4277 200 NCBG staff 1993-03-01 View
7372 4953 202 NCBG staff 1992-01-01 View
7560 5134 203 NCBG staff 1992-01-01 View
8353 5838 204 NCBG staff 1993-01-01 View
8787 6132 2 NCBG staff 0000-00-00 View
12308 9218 77 Liloia 2008-03-14 View
12309 9218 67 Liloia 2008-03-14 View
12310 9218 80 Liloia 2008-03-14 View
12400 233 16 Liloia 0000-00-00 View
12647 9394 15 Liloia 2021-03-15 View

USDA PLANTS DATABASE

USDA Symbol: HOCA4
USDA Common Name: Azure Bluet
Native Status: L48 (N), CAN (N), SPM (I)
Distribution: USA (AL, AR, CT, DC, DE, GA, IL, IN, KY, LA, MA, MD, ME, MI, MO, MS, NC, NH, NJ, NY, OH, PA, RI, SC, TN, VA, VT, WI, WV), CAN (NB, NS, ON, QC), FRA (SPM)
Duration: Perennial
Growth Habit: Forb/herb

NATIONAL WETLAND INDICATOR STATUS

Region:AGCPAKAWCBEMPGPHIMWNCNEWMVE
Status: FAC FACU FACU FAC FACU

This information is derived from the U.S. Army Corps of Engineers 2016 National Wetland Plant List, Version 3.3 (Lichvar, R.W., D.L. Banks, W.N. Kirchner, and N.C. Melvin. 2016. The National Wetland Plant List: 2016 wetland ratings. Phytoneuron 2016-30: 1-17. Published 28 April 2016. ISSN 2153 733X). Regions: AGCP-Atlantic and Gulf Coastal Plain, AK-Alaska, AW-Arid West, CB-Caribbean, EMP-Eastern Mountains and Piedmont, GP-Great Plains, HI-Hawaii, MW-Midwest, NCNE-Northcentral and Northeast, WMCV-Western Mountains, Valleys & Coast

WEAKLEY FLORA

SCIENTIFIC NAME: Houstonia caerulea
COMMON NAME: Quaker Ladies, Innocence, Common Bluet
SYNONYMY: [= G, K, Mo, Pa, RAB, S, Va, W, WV, X, Y; = Houstonia caerulea var. caerulea - F; > H. caerulea var. faxonorum Pease & A.H. Moore - F; = Hedyotis caerulea (Linnaeus) Hooker - C, GW; < Hedyotis caerulea - Q]
PHENOLOGY: (Late Jan-) Apr-Jul; May-Aug.
HABITAT: Forests, woodlands, openings, lawns, a wide variety of disturbed sites.
COMMENTS: ME, ON, and WI south to s. GA, s. AL, w. LA, and OK. The flowers of this species and H. serpyllifolia are very similar; H. caerulea is a somewhat duller blue.
RANGE MAP: Houstonia caerulea.png

Key to Map Symbols
ABOUT FAMILY (Weakley Flora)
Rubiaceae A.L. de Jussieu 1789 (Madder Family)
SUMMARY: A family of about 630-650 genera and 10,200-13,000 species, trees, shrubs, vines, and rarely herbs, cosmopolitan, but especially diverse in tropical and subtropical areas. Subfamily and tribe classification follows Bremer & Eriksson (2009).
REFERENCE: Bremer & Eriksson (2009); Rogers (1987, 2005).
ABOUT GENUS (Weakley Flora)
Houstonia L. (Bluet)
SUMMARY: The generic limits of Houstonia, Hedyotis, Oldenlandia, and Stenaria have been controversial, with much shuffling of generic configuration. It now appears that Houstonia should be recognized as a genus separate from Hedyotis and Oldenlandia, with Stenaria included in Houstonia (Guo et al. 2013; Wikström et al. 2013, and other references).
REFERENCE: Terrell (1959)=Z; Terrell (1991)=Y; Terrell (1996)=X; Rogers (1987)=Q; Ward (2004c)=V; Church & Taylor (2005); Church (2003); Turner (1995b)=U; Terrell (2001)=M; Rogers (2005); Terrell (2007); Guo et al. (2013); Wikström et al. (2013). Key adapted in part from the references.

HERBARIUM RESOURCES

SERNEC: Find Houstonia caerulea in Southeast Regional Network of Experts and Collections (if available)
UNC SERNEC: Find Houstonia caerulea in University of North Carolina Chapel Hill Herbarium - Southeast Regional Network of Experts and Collections (if available)

WEB RESOURCES

USDA: Find Houstonia caerulea in USDA Plants
NPIN: Find Houstonia caerulea in NPIN Database
FNA: Find Houstonia caerulea in the Flora of North America (if available)
Google: Search Google for Houstonia caerulea

NCBG IMAGE RECORDS

ID IMAGE1: 9148
ID IMAGE2: 0
ID IMAGE3: 9148

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37 photo(s) available in the Image Gallery

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