Cerastium pumilum
Caryophyllaceae subfam. alsinoideae
dwarf mouse-ear, dwarf mouse-ear chickweed, European chickweed, sticky mouse-ear chickweed
erect or ascending, branching near base, 2–12 cm, covered with glandular and eglandular hairs; small axillary tufts of leaves usually absent.
prostrate to ascending or erect, simple or branched.
not marcescent, sessile;
blade 5–15 × 3–6 mm, hairy;
basal with blades oblanceolate, spatulate, petiolelike, apex obtuse;
cauline with blades lanceolate, elliptic, or ovate, apex acute to obtuse.
opposite, connate proximally or not, often petiolate (basal leaves), not stipulate;
blade subulate or linear to spatulate, lanceolate, or broadly ovate, seldom succulent.
lax, 3–15-flowered (rarely more) cymes;
bracts lanceolate: proximal usually foliaceous, distal smaller, usually with narrow, scarious margins and apex, glandular-pubescent.
terminal or axillary cymes, or flowers solitary;
bracts foliaceous or reduced, herbaceous to scarious (or rarely absent);
involucel bracteoles absent.
erect, curved distally, 3–8(–10) mm, longer than capsule, glandular-pubescent.
present or rarely flowers sessile.
sepals green, sometimes red tipped, oblong-lanceolate, 4–5 mm, margins narrow, apex acute, pubescent, hairs short, stiff, glandular, not projecting beyond scarious, glabrous apex;
petals white or purple-tinged, with branching veins, oblanceolate, ca. 5 mm, ± equaling sepals, apex 2-fid for ca. 1/4 length;
stamens 5;
styles 5.
bisexual or seldom unisexual, sometimes inconspicuous;
perianth and androecium hypogynous or perigynous, often slightly;
hypanthium cup-, dish-, or disc-shaped;
sepals (4–)5, distinct or seldom connate basally, sometimes hooded, not awned;
petals absent or (1–)4–5, usually white, sometimes translucent, yellowish white, pink, or brownish, seldom clawed, auricles absent, coronal appendages absent, blade apex entire or 2-fid, sometimes jagged or emarginate, rarely laciniate;
stamens absent or (1–)5(–10), in 1 or 2 whorls, arising from base of ovary, a nectariferous disc, or sometimes the hypanthium or hypanthium rim;
staminodes absent or 1–5(–8);
ovary 1- or rarely 3-locular (Wilhelmsia);
styles (2–)3–5(–6), distinct;
stigmas (2–)3–5(–6).
capsules, or rarely utricles (Scleranthus), opening by (2–)3–6, occasionally 8 or 10 valves or (3 or) 6–10 teeth;
carpophore present or often absent.
narrowly cylindric, slightly curved upward, 6–9 mm, ca. 2 times as long as sepals;
teeth 10, erect, margins convolute.
dark brown, deltoid, 0.6–0.7 mm, tuberculate;
testa not inflated.
1–60+, yellowish or tan to dark red or often brown or black, usually reniform or triangular to circular and laterally compressed or ovoid to globose, rarely oblong and dorsiventrally compressed (Holosteum);
embryo usually peripheral and curved, rarely central and straight (Holosteum).
= 6–15, 17–19, 23.
= 72.
Cerastium pumilum
Caryophyllaceae subfam. alsinoideae
North American material referred to here as Cerastium pumilum is very variable. At one extreme are plants resembling small annual forms of C. fontanum, with relatively short, broad capsules, petals slightly longer than the sepals, and sepals that are usually red at the tips. At the other extreme are plants with relatively long, narrow capsules resembling impoverished diffuse-inflorescenced C. glomeratum, with short petals and no red pigment. The latter are probably referable to C. pumilum subsp. glutinosum. B. Jonsell and T. Karlsson (2001+, vol. 2) treated C. glutinosum as a distinct species in Scandinavia, but the correlation of characters that they gave to distinguish C. glutinosum from C. pumilum does not occur in most North American material that I have examined. Hence, the recognition of a single species, possibly with two subspecies, as in Flora Europaea (T. G. Tutin et al. 1964–1980, vol. 1), appears to be more appropriate. The problem may arise from North American material having been introduced from several sources, whereas Scandinavian material may consist of two native genotypes that do not show the complete range of variation in the species.
Cerastium pumilum can look like a small annual form of C. fontanum but differs in its smaller capsules and the characteristic rather short, glandular hairs on the sepals, bracts, and inflorescence. It can be separated from C. semidecandrum by the much narrower scarious margins of the sepals and bracts and by the branching veins in the petals, which tend to be slightly longer and more conspicuous than in C. semidecandrum. Some forms of C. glomeratum have a very open inflorescence and may be confused with C. pumilum, but C. glomeratum has ten stamens, a narrower capsule, all the bracts herbaceous, and long, eglandular hairs (often mixed with glandular ones) on the bracts and sepals.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Genera 30, species ca. 1040 (16 genera, 137 species in the flora).
Alsinoideae, often considered basal in the family and the least specialized, is in some ways the most heterogeneous of the subfamilies. Members of its largest tribe (Alsineae) share the following characteristics: stipules absent, sepals free or at most basally connate, and capsular fruits. Indehiscent fruits, relatively short hypanthia, and other floral reductions occur in varying combinations in the approximately 30 species placed in four other tribes. A broad molecular survey of Alsinoideae has revealed two major lineages and lack of support for the existing tribal circumscriptions (M. Nepokroeff et al. 2002). About three-fourths of the species are members of Arenaria, Cerastium, Minuartia, and Stellaria.
Attempts have been made to move Scleranthus (fruit a utricle surrounded by an enlarged hypanthium) from Alsinoideae to either Paronychioideae (J. Hutchinson 1973, as Illecebraceae) or Scleranthaceae (A. Takhtajan 1997). Recent molecular and morphological studies by R. D. Smissen et. al. (2002, 2003) supported its retention in the Alsinoideae.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
BC, 
OR, 
WA - Local Web sites:
Flora NW, 
Go Botany, 
IL Wildflowers, 
KS Wildflowers, 
MD Biodiversity, 
MI Flora, 
MO Plants, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
