Stellaria

Plants annual, winter annual, or perennial. Taproots usually slender, perennial taxa often rhizomatous, rooting at nodes. Stems prostrate to ascending or erect, simple or branched, terete or 4-angled. Leaves sometimes connate basally into sheath, often sessile; blade 1-veined, linear or lanceolate to ovate or deltate, succulent (S. crassifolia [gemmae], S. fontinalis, S. humifusa, and S. irrigua) or not, apex acute or obtuse. Inflorescences terminal, open cymes, rarely axillary (S. alsine, S. americana) or umbellate (S. umbellata), or terminal or axillary solitary flowers; bracts paired (1 in S. dicranoides), foliaceous, scarious and reduced, or absent. Pedicels erect, sometimes reflexed in fruit, glabrous or pubescent, not glandular. Flowers usually bisexual (S. dicranoides unisexual); perianth and androecium hypogynous or weakly perigynous; hypanthium cup- or disc-shaped; sepals (4–)5, distinct, green, occasionally purple tinged (S. irrigua) or red proximally (S. pallida), lanceolate to ovate-triangular, 2–12 mm, herbaceous (rarely coriaceous), margins often white, scarious, apex acute, acuminate, or obtuse, not hooded; petals (1–)5 or absent, white (sometimes translucent in S. borealis), not clawed, blade apex 2-fid usually for 2/3–4/5 its length (S. holostea occasionally laciniate); nectaries at base of filaments opposite sepals usually present, disc sometimes prominent; stamens (1–)5 or 10 or absent, arising from nectariferous disc (prominent in S. dicranoides and S. irrigua) at ovary base; filaments distinct; staminodes absent; styles [2–]3(–5), capitate to clavate, 0.2–7 mm, glabrous proximally; stigmas [2–]3(–5), terminal or subterminal, papillate (30×). Capsules globose to conic, opening by 3 or 6, occasionally 4, 8, or 10 ascending to recurved valves; carpophore present or absent. Seeds (1–)3–20+, yellow-brown to dark brown, globose to ellipsoid, laterally compressed, rarely shiny, papillate or rugose, rarely smooth, marginal wing absent, appendage absent. x = 10, 11, 12, 13, 15.

Distribution

Worldwide, mainly north-temperate regions.

Discussion

Species ca. 120 (29 in the flora).

I have not attempted to present an infrageneric classification for Stellaria. Although several species complexes can be identified within the genus (e.g., S. media, S. longipes, S. calycantha), there are significant problems with accepting the most recent scheme (F. Pax and K. Hoffmann 1934c). Stellaria jamesiana is now placed in Pseudostellaria and S. aquatica in Myosoton. As well, S. dicranoides and S. fontinalis probably should be placed in other genera (see comments under those species). Additional study is warranted to determine both the generic circumscription of Stellaria and species relationships within the genus.

Selected References

Chinnappa, C. C. and J. K. Morton. 1976. Studies on the Stellaria longipes Goldie complex—Variation in wild populations. Rhodora 78: 488–501.

Chinnappa, C. C. and J. K. Morton. 1984. Studies on the Stellaria longipes Goldie complex (Caryophyllaceae): Biosystematics. Syst. Bot. 9: 60–73.

Chinnappa, C. C. 1985. Studies in the Stellaria longipes complex (Caryophyllaceae): Interspecific hybridization. I. Triploid meiosis. Canad. J. Genet. Cytol. 27: 318–321.

Chinnappa, C. C. and J. K. Morton. 1991. Studies on the Stellaria longipes complex (Caryophyllaceae): Taxonomy. Rhodora 93: 129–135.

Emery, R. J. N. and C. C. Chinnappa. 1994. Morphological variation among members of the Stellaria longipes complex: S. longipes, S. longifolia, and S. porsildii (Caryophyllaceae). Pl. Syst. Evol. 190: 69–78.

Hultén, E. 1943. Stellaria longipes and its allies. Bot. Not. 1943: 251–270.

Morton, J. K. and R. K. Rabeler. 1989. Biosystematic studies on the Stellaria calycantha (Caryophyllaceae) complex. I. Cytology and cytogeography. Canad. J. Bot. 67: 121–127.

Porsild, A. E. 1963. Stellaria longipes Goldie and its allies in North America. Bull. Natl. Mus. Canada 186: 1–35.

Rabeler, R. K. 1986. Revision of the Stellaria calycantha (Caryophyllaceae) Complex and Taxonomic Notes on the Genus. Ph.D. dissertation. Michigan State University.

Lower Taxa

Stellaria alaskana, Stellaria alsine, Stellaria americana, Stellaria borealis, Stellaria calycantha, Stellaria corei, Stellaria crassifolia, Stellaria crispa, Stellaria cuspidata, Stellaria dicranoides, Stellaria fontinalis, Stellaria graminea, Stellaria holostea, Stellaria humifusa, Stellaria irrigua, Stellaria littoralis, Stellaria longifolia, Stellaria longipes, Stellaria media, Stellaria neglecta, Stellaria nitens, Stellaria obtusa, Stellaria pallida, Stellaria palustris, Stellaria parva, Stellaria porsildii, Stellaria pubera, Stellaria ruscifolia, Stellaria umbellata

Key

1	Mid-stem and proximal leaves distinctly petiolate, broadly lanceolate to ovate or deltate	> 2
1	Mid-stem and proximal leaves sessile to shortly petiolate; blades elliptic, ovate, lanceolate, linear, or linear-lanceolate	> 8
2	Leaf blade bases cordate to truncate (rarely abruptly rounded)	Stellaria cuspidata
2	Leaf blade bases round or cuneate	> 3
3	Flowers large, usually 10 mm or more diam.; petals usually exceeding sepals	> 4
3	Petals equaling or shorter than sepals, or absent; flowers less than 10 mm diam	> 5
4	Sepals obtuse to acute, 3.5-6 mm	Stellaria pubera
4	Sepals acuminate, (5-)7-10(-12) mm	Stellaria corei
5	Flowers solitary in axils of mid and distal stem leaves	Stellaria obtusa
5	Flowers several in foliaceous terminal cymes	> 6
6	Sepals 5-6.5 mm; stamens 8-10; seeds 1.1-1.7 mm; tubercles taller than broad, apex acute	Stellaria neglecta
6	Sepals usually 3-5(-6) mm; stamens 1-5(-8); seeds 0.4-1.3 mm; tubercles usually broader than tall, apex usually obtuse	> 7
7	Stamens 3-5(-8); sepals 4.5-5(-6) mm; seeds 0.9-1.3 mm diam.; petals usually present; plants usually green	Stellaria media
7	Stamens 1-3 or absent; sepals 3-4 mm; seeds mostly 0.5-0.9 mm diam.; petals usually absent; plants usually yellowish green	Stellaria pallida
8	Inflorescences, or flowers when solitary, in axils of foliage leaves on mid or distal stem	> 9
8	Inflorescences with most flowers terminal, either several in bracteate inflorescence or solitary on long-ascending pedicels	> 18
9	Petals equaling or longer than sepals	> 10
9	Petals shorter than sepals, or absent	> 13
10	Sepals narrowly lanceolate-triangular, prominently 3-veined, margins straight	Stellaria crassifolia
10	Sepals lanceolate to ovate-lanceolate, 1- or obscurely 3-veined, margins convex	> 11
11	Seeds prominently papillate, papillae taller than broad; sepals pubescent	Stellaria parva
11	Seeds smooth, rugose, or shallowly tuberculate, not papillate; sepals glabrous	> 12
12	Leaf blades succulent, elliptic to elliptic-lanceolate, 4-15 × 1-5 mm	Stellaria humifusa
12	Leaf blades not succulent, linear to linear-lanceolate, 27-35 × 2-3 mm	Stellaria porsildii
13	Plants forming dense cushions, mid and distal stem internodes shorter than leaves	> 14
13	Plants creeping to straggling or ascending, sometimes forming mats, but not forming cushions, internodes equaling or longer than leaves	> 15
14	Stamens 5; petals present, deeply divided into 2 narrowly elliptic lobes	Stellaria irrigua
14	Stamens 10; petals absent	Stellaria dicranoides
15	Leaf blades narrowly elliptic to lanceolate, oblanceolate, or linear	> 16
15	Leaf blades broadly elliptic to ovate	> 17
16	Flowers solitary in distal leaf axils	Stellaria fontinalis
16	Flowers in axillary inflorescences in mid and distal leaf axils	Stellaria alsine
17	Sepals obtuse at apex with ± obscure veins; styles shorter than 0.5 mm, curled; capsules globose to broadly ovoid	Stellaria obtusa
17	Sepals acute to acuminate at apex with 3 prominent veins; styles ca. 1 mm, spreading to ascending; capsules ovoid to ovoid-ellipsoid	Stellaria crispa
18	Bracts scarious or with scarious margins	> 19
18	Bracts or subtending leaf blades without scarious margins	> 26
19	Capsules ca. equaling or shorter than sepals	> 20
19	Capsules longer than sepals	> 22
20	Plants annual	Stellaria nitens
20	Plants perennial	> 21
21	Plants compact; stems ascending, 3-10(-20) cm; petals equaling or shorter than sepals	Stellaria alaskana
21	Plants coarse; stems straggling with erect branches, 20-60 cm; petals 1.5-2 times as long as sepals	Stellaria palustris
22	Inflorescences subumbellate; petals absent	Stellaria umbellata
22	Inflorescences cymose or flowers solitary; petals present	> 23
23	Plants delicate, creeping, often forming mats; flowers solitary and axillary or in small, few-flowered, leafy cymes; leaf blades variable in shape, midribobscure	Stellaria crassifolia
23	Plants not with the above combination of characters; leaf blades with prominent midrib	> 24
24	Leaf blades linear-elliptic, broadest at middle or distally; angles of stems and/or margins of leaf blades minutely papillate-scabrid (30×)	Stellaria longifolia
24	Leaf blades lanceolate to linear-lanceolate, broadest proximally; angles of stems and/or margins of leaf blades not papillate-scabrid (soft hairs of cilia may be present)	> 25
25	Sepals narrowly triangular or lanceolate, margins straight, veins 3, forming prominent ridges; seeds coarsely rugose in concentric rings; plants coarse; stems ascending, straggling; inflorescences muchbranched, many-flowered	Stellaria graminea
25	Sepals lanceolate to ovate-lanceolate, margins convex, veins 1-3, not forming ridges; seeds shallowly tuberculate to smooth; stems erect to straggling; flowers solitary or inflorescences few-flowered	Stellaria longipes
26	Flowers 20-30 mm diam.; petals 8-14 mm, longer than sepals; leaf blades narrowly lanceolate, 4-8 cm, apex acuminate	Stellaria holostea
26	Plants not having the above combination of characters	> 27
27	Leaves widest at or above middle	> 28
27	Leaves widest towards base	> 31
28	Plants glandular-puberulent; pedicels arcuate, pushing capsule into substrate; seeds 3-6, ca. 2.5 mm diam	Stellaria americana
28	Plants eglandular; other characters not as above	> 29
29	Sepals narrowly lanceolate-triangular; plants creeping, forming mats usually shorter than 5 cm	Stellaria crassifolia
29	Sepals ovate to ovate-triangular; plants with diffusely branched or ascending flowering stems taller than 5 cm	> 30
30	Petals 4-8 mm, conspicuous, white; sepals 3.5-6 mm	Stellaria pubera
30	Petals shorter than 3 mm, inconspicuous, white or translucent; sepals2-3(-4) mm	Stellaria borealis
31	Plants straggling to scandent; stems to 60 cm; leaf blades ovate to ovate-lanceolate, 10-45 × 4-20 mm; inflorescences terminal leafy cymes	Stellaria littoralis
31	Plants not having the above combination of characters	> 32
32	Sepals 2-3(-4) mm; open flowers less than 5 mm diam.; petals not exceeding sepals, inconspicuous or absent	> 33
32	Sepals 3.5 mm or longer; open flowers 5 mm or more diam.; petals equaling or exceeding sepals, conspicuous	> 34
33	Capsules broadly ovoid to globose, to 1.5 times as long as broad; styles less than 1 mm; sepals in open flowers less than 2.5 mm, veins obscure (rarely 1)	Stellaria calycantha
33	Capsules ovoid, more than 1.5 times as long as broad; styles longer than 1 mm; sepals in open flowers more than 2.5 mm with 1-3 prominent veins	Stellaria borealis
34	Sepals 4.5-6 mm; leaf blades ovate to broadly lanceolate, coriaceous, apex spinous; capsules equaling sepals	Stellaria ruscifolia
34	Sepals 3.5-5 mm; leaf blades lanceolate to linear-lanceolate, not strongly coriaceous, apex acute to acuminate, not spinous; capsules 1.5-2 times as long as sepals	Stellaria longipes