Herbs, annual, rarely perennial (A. linifolia); hemiparasitic, rarely rhizomatous (A. linifolia). Stems erect, rarely leaning, rarely fleshy, glabrous, hispid, scabrous, scabridulous, glabrate, sericeous, or papillate. Leaves cauline, opposite or subopposite, rarely alternate (A. filifolia); petiole absent; blade not leathery, rigid, rarely fleshy, margins entire, rarely proximally cleft, pinnatifid, or 2-pinnatifid. Inflorescences terminal, racemes or panicles, rarely racemiform or spikelike; bracts present. Pedicels present; bracteoles absent. Flowers: sepals 5, calyx radially, rarely bilaterally, symmetric, campanulate to hemispheric, turbinate, or funnelform, lobes obtusely to acutely subulate or deltate, acute- to acuminate-triangular, or lanceolate; petals 5, corolla pale pink to rose purple or purple, rarely white, throats usually with 2 abaxial yellow lines and red spots within, bilabiate, funnelform to campanulate, abaxial throat gibbous, rounded, or straight, abaxial lobes 3, adaxial 2; stamens 4, didynamous; filaments glabrate to lanate; staminode 0; ovary 2-locular, placentation axile; stigma linear, rarely 2-lobed (A. neoscotica). Capsules: dehiscence loculicidal. Seeds 60–600, yellow, tan, brown, or black, angled, wings absent. x = 13.

Distribution

c, e North America, Mexico, West Indies, Central America, South America.

Discussion

Species ca. 60 (34 in the flora).

F. W. Pennell (1929, 1935) placed Agalinis auriculata and A. densiflora in Tomanthera based on their retrorsely hispid stems, calyx lobes longer than the tube, leaf blades lanceolate to ovate and lobed, anthers of the proximal pair of stamens shorter than anthers of the distal pair, and absence of yellow lines in the corolla. With the exception of hispid stems, these characteristics occur in other species of Agalinis and/or do not occur with regularity in both A. auriculata and A. densiflora.

Agalinis is an attractive component of the fall flora; corollas last less than a day, usually falling in early afternoon. Some species of Agalinis darken when dried, some turning nearly black. The stem leaves of some species produce axillary fascicles. Some have incrustations of silica, which appear as smooth, gray or whitish, marbled patches or striations on leaves and stems. Siliceous hairs are also common.

For descriptions presented here, corolla length is the distance from the base of the sinus between the abaxial calyx lobes to the apex of the extended (not reflexed) mid abaxial corolla lobe. Corolla throat is the flared portion of the corolla between the cylindrical tube, which is held within the calyx, and the bases of the corolla lobes. Because the delicate corollas are easily distorted by pressing, it is particularly useful to note in the field whether the adaxial corolla lobes are reflexed or project flatly forward or arch forward, whether the two adaxial lobes are obviously shorter than the three abaxial lobes, and whether the adaxial side of the corolla throat is shorter than, or about equal to, the abaxial side of the throat. The interior of the distal corolla throat at the bases of the adaxial corolla lobes should be examined for a band of relatively long hairs.

Molecular phylogenetic studies support monophyly for 24 of the 29 taxa investigated (J. B. Pettengill and M. C. Neel 2008). Agalinis acuta was not differentiated from A. decemloba by molecular or morphological data (Pettengill and Neel 2008, 2011); A. decemloba includes A. acuta as treated here. Agalinis paupercula clustered with A. purpurea in molecular phylogenetic analyses and is treated here as a variety of A. purpurea. Agalinis tenella clustered with A. decemloba; A. tenella is treated here as a species based on morphological data.

Key

1 Bracts longer than pedicels. > 2
2 Leaf blade margins entire or mid to distal with 1 or 2 proximal lobes, or pinnatifid distally or 2-pinnatifid; bract margins pinnatifid or with proximal lobes; branches retrorsely short-sericeous and hispid; calyx lobes (5–)7–13 mm. > 3
3 Calyx tubes hirsute; leaf blades lanceolate, margins entire or mid to distal with 1 or 2 proximal lobes. Agalinis auriculata
3 Calyx tubes densely, finely scabridulous and hispid; leaf blades triangular-ovate, margins pinnatifid distally or 2-pinnatifid. Agalinis densiflora
2 Leaf blade margins entire, rarely proximalmost 3-cleft; bract margins entire; branches glabrous, glabrate, or scabridulous to scabrous; calyx lobes 0.2–8 mm. > 4
4 Leaf blades fleshy, adaxial surfaces with sessile, dome-shaped hairs. > 5
5 Calyx lobes narrowly lanceolate, 2.7–7 mm; abaxial corolla lobes glabrous externally; capsules obovoid to oblong, 10–12 mm. Agalinis calycina
5 Calyx lobes deltate, 0.5–2 mm; abaxial corolla lobes pilose externally; capsules subglobular to globular, 5–7 mm. > 6
6 Stems 70–160 cm, (perennials); corollas 25–35 mm, lobes 6–14 mm; styles 15–28 mm; pedicels 5–25 mm. Agalinis linifolia
6 Stems 5–75 cm, (annuals); corollas 7.5–21 mm, lobes 2.5–6 mm; styles 6–13 mm; pedicels 2.5–11 mm. Agalinis maritima
4 Leaf blades not fleshy, adaxial surfaces scabridulous to scabrous. > 7
7 Corollas: abaxial lobes glabrous externally; capsules ovoid-oblong; calyx lobes triangular-lanceolate or lanceolate. > 8
8 Leaves: blades linear to filiform, 0.4–1.5(–2) mm wide, surfaces scabrous; axillary fascicles well developed; pedicels 4–20 mm. Agalinis aspera
8 Leaves: blades narrowly lanceolate to elliptic-lanceolate, sometimes proximalmost 3-cleft, 2–6(–7) mm wide, surfaces scabridulous to slightly scabrous; axillary fascicles absent, rarely present; pedicels 1–5(–6) mm. Agalinis heterophylla
7 Corollas: abaxial lobes pilose externally; capsules globular; calyx lobes deltate-subulate, triangular, or triangular-subulate, rarely lanceolate or triangular-lanceolate. > 9
9 Pedicels 6–25 mm; corollas: adaxial lobes projected over distal anthers, throats glabrous within across bases and sinus of adaxial lobes. Agalinis tenuifolia
9 Pedicels 0.5–8 mm; corollas: adaxial lobes spreading, erect, or reflexed-spreading, rarely projected distal to corolla mouth, throats villous within across bases and sinus of adaxial lobes. > 10
10 Calyx lobes deltate-subulate, 0.2–1 mm; leaf blades filiform, 0.2–0.8 mm wide; inflorescences racemiform, with pseudoterminal flowers. Agalinis plukenetii
10 Calyx lobes triangular, triangular-subulate, triangular-lanceolate, or lanceolate, 0.6–4(–5) mm; leaf blades +/- linear to linear-filiform, linear-lanceolate, or linear-elliptic to elliptic, 0.4–5 mm wide; inflorescences racemes. > 11
11 Leaf blades linear-elliptic to elliptic; calyx lobes triangular-lanceolate; styles included; stems 5–30(–47) cm. Agalinis neoscotica
11 Leaf blades +/- linear to linear-filiform or linear-lanceolate; calyx lobes triangular to triangular-subulate or lanceolate; styles exserted, rarely included; stems (7–)20–200 cm. > 12
12 Leaves: axillary fascicles well developed, shorter than or equal to subtending leaves; branches moderately to often copiously scabrous or scabridulous on faces and angles. > 13
13 Corollas 22–36 mm, lobes 5–12 mm; leaf blades 15–40(–50) mm; styles 14–22 mm, strongly exserted; stems (10–)50–200 cm. Agalinis fasciculata
13 Corollas 12–14 mm, lobes 3–5 mm; leaf blades 10–15(–20) mm; styles 4–7.7 mm, included or slightly exserted; stems 20–40(–50) cm. Agalinis georgiana
12 Leaves: axillary fascicles absent or shorter than subtending leaves; branches glabrous, glabrate, or scabridulous to sparsely scabrous. > 14
14 Branches ascending, slightly quadrangular-ridged distally; leaf blades linear to linear-filiform, 0.5–1.4 mm wide; calyx lobes triangular-subulate, keeled; seeds black. Agalinis harperi
14 Branches ascending, spreading, or arching, quadrangular-ridged or winged distally; leaf blades narrowly linear, linear, or linear-lanceolate, 0.5–4(–5) mm wide; calyx lobes triangular, lanceolate, or triangular-subulate, not keeled; seeds dark brown. Agalinis purpurea
1 Bracts shorter than, sometimes equal to, pedicels. > 15
15 Leaves slightly divergent or appressed to strongly ascending, blades subulate to narrowly triangular, 0.5–3 mm. > 16
16 Inflorescences racemes, sometimes with 1–3 mm, floriferous axillary branches; pedicels 1–3(–4) mm; branches stiffly ascending, quadrangular; corolla throats pilose externally. Agalinis aphylla
16 Inflorescences paniculate with solitary flowers; pedicels 3–10(–12) mm; branches widely and laxly spreading, nearly terete; corolla throats glabrous externally. Agalinis filicaulis
15 Leaves erect, erect-ascending, ascending, spreading-ascending, recurved, spreading, arching, or reflexed, rarely appressed or ascending-appressed, blades subulate, filiform, linear, linear-filiform, linear-spatulate, linear-elliptic, linear-lanceolate, elliptic, spatulate, or lanceolate, (1–)4–70 mm. > 17
17 Abaxial corolla lobes pilose externally. > 18
18 Leaves (alternate, blades fleshy), axillary fascicles equal to or longer than subtending leaves. Agalinis filifolia
18 Leaves (opposite, blades not fleshy), axillary fascicles absent or shorter than subtending leaves. > 19
19 Corollas: adaxial lobes projected over distal anthers, throats glabrous within across bases and sinus of adaxial lobes; leaf blades narrowly linear to linear-lanceolate; capsules globular; seeds tan to brown. Agalinis tenuifolia
19 Corollas: adaxial lobes recurved, reflexed, or reflexed-spreading, throats villous within across bases and sinus of adaxial lobes; leaf blades filiform to narrowly linear; capsules elliptic-ovate or globular-ovoid; seeds black or yellowish tan. > 20
20 Inflorescences racemes, sometimes interrupted by short floriferous branches, flowers 2 per node; capsules elliptic-ovate. Agalinis setacea
20 Inflorescences racemiform or racemose-paniculate, flowers 1 per node; capsules globular-ovoid. > 21
21 Calyx lobes triangular-lanceolate; branches spreading-ascending; seeds yellowish tan; pedicels spreading-ascending. Agalinis gattingeri
21 Calyx lobes deltate-subulate; branches widely and laxly ascending; seeds black; pedicels widely spreading. Agalinis laxa
17 Abaxial corolla lobes glabrous externally. > 22
22 Pedicels scabrous; leaves: axillary fascicles usually 1/2+ length of subtending leaves, sometimes absent. > 23
23 Corollas: lobes unequal, 2–6 mm, adaxial arched over anthers; calyx lobes triangular-subulate, recurved, 0.6–1.5 mm. Agalinis homalantha
23 Corollas: lobes equal, 6–12 mm, adaxial spreading; calyx lobes subulate, erect, 0.1–0.6 mm. Agalinis pulchella
22 Pedicels glabrous or +/- scabridulous; leaves: axillary fascicles absent or shorter than subtending leaves. > 24
24 Corolla throats glabrous externally, sometimes pilose externally proximal to sinuses. > 25
25 Calyces: tubes 1.5–3 mm, lobes 0.1–0.5 mm, deltate; capsules 3–5 mm; styles 6–9(–10) mm; branches widely spreading. Agalinis divaricata
25 Calyces: tubes 3–5.5 mm, lobes 0.4–2.5 mm, triangular-subulate to subulate or triangular-lanceolate; capsules 5–8 mm; styles 12–17 mm; branches ascending-spreading. > 26
26 Leaf blades filiform to narrowly linear; corollas: lobes unequal, adaxial arched over anthers; calyx lobes triangular-subulate to subulate, 0.4–0.8(–1.3) mm. Agalinis edwardsiana
26 Leaf blades linear; corollas: lobes equal, adaxial erect to spreading; calyx lobes triangular-lanceolate, 0.8–2.5 mm. Agalinis strictifolia
24 Corolla throats pilose externally. > 27
27 Leaves: proximal and mid reflexed or recurved, distal spreading; anthers 2–3.8 mm; styles 11–16.5 mm; corolla throats glabrous within across bases of adaxial lobes, sparsely villous at sinus. > 28
28 Calyces hemispheric-campanulate; inflorescences racemes; corollas 17–30 mm. Agalinis caddoensis
28 Calyces funnelform-obconic; inflorescences racemiform-paniculate; corollas 15–24 mm. Agalinis navasotensis
27 Leaves erect, erect-ascending, ascending-appressed, spreading, or spreading-ascending; anthers 0.6–2.6 mm; styles 3–12 mm; corolla throats villous within across bases and sinus of adaxial lobes. > 29
29 Branches stiffly arching-ascending, ascending, erect-ascending, or spreading-ascending, quadrangular; capsules globular to oblong; leaves erect to erect-ascending, or ascending, or proximal slightly spreading, distal sometimes ascending-appressed. > 30
30 Leaf blades subulate, elliptic, or filiform; anthers 1.8–2.6 mm; corollas 15–25 mm, pink to dark pink, with 2 yellow lines and red spots present in abaxial throat, lobes 4–7(–9) mm. Agalinis oligophylla
30 Leaf blades linear-elliptic, narrowly spatulate, linear-spatulate, or linear; anthers 0.6–2.1 mm; corollas 8–16(–17) mm, whitish to pink, with 2 yellow lines and red or pink spots pale or absent in abaxial throat, lobes 3–5 mm. > 31
31 Calyx lobes deltate, 0.2–0.5 mm; leaf blades linear-elliptic to narrowly spatulate; anthers 1.5–2.1 mm; stems 30–80(–100) cm. Agalinis obtusifolia
31 Calyx lobes triangular-subulate, 0.3–1.2 mm; leaf blades linear; anthers 0.6–1.2 mm; stems 10–50(–60) cm. Agalinis skinneriana
29 Branches: proximal arching upward, others spreading-ascending to laxly and widely spreading, subterete to quadrangular-ridged; capsules ovoid, obovoid-oblong, ovoid-globular, or obovoid; leaves spreading to spreading-ascending. > 32
32 Calyx lobes subulate to triangular or lanceolate, (0.2–)0.5–2.5 mm. > 33
33 Branches ascending to spreading, quadrangular-ridged; capsules ovoid; calyx lobes subulate to triangular, (0.2–)0.5–1.5(–2) mm; styles (5–)7–12 mm. Agalinis decemloba
33 Branches laxly and widely spreading, proximal arching upward, strongly quadrangular; capsules obovoid; calyx lobes lanceolate, 1.3–2.5 mm; styles 3–5 mm. Agalinis viridis
32 Calyx lobes deltate-subulate or subulate, 0.2–0.5 mm. > 34
34 Corolla lobes 3–4.5 mm; anthers 1.2–1.8 mm; styles 5–7 mm; leaf blades linear to linear-spatulate; capsules obovoid-oblong; seeds golden brown. Agalinis flexicaulis
34 Corolla lobes 4–7.3 mm; anthers 1.7–2.5 mm; styles 7–9 mm; leaf blades filiform to linear-filiform; capsules ovoid-globular; seeds yellow. Agalinis tenella