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Subfamily

III. Subfam. Ajugoideae Kostel. (1834).

Subfam. Teucrioideae (Dumort.) Caruel (1884).

Description

Shrubs, subshrubs, and annuals, strongly aromatic; leaves opposite, petiolate or sessile, elliptic to linear or ovate, usually entire; inflorescence of axillary cymes, sometimes reduced to solitary flowers or grading into paniculiform terminal thyrse; calyx actinomorphic or zygomorphic, accrescent, 5-lobed (3/2), posterior lobes in zygomorphic calyces forming long upper lip (appearing to be lower lip in fruit due to post-anthesis resupination), anterior lobes shorter; corolla violet to pink, zygomorphic, 5-lobed, four posterior lobes usually similar, entire, anterior-most lobe larger, entire or erose, tube straight or distally upturned, corolla in bud strongly asymmetrical to nearly symmetrical; stamens 4, usually didynamous, usually long-exserted, filaments strongly arched to nearly straight, thecae divergent to nearly parallel, confluent at dehiscence; pollen with supratectal spines or spinules, columellate stratum of exine undifferentiated or composed of branched columellae; ovary shallowly 4-lobed; stigma-lobes equal or unequal; disc well developed to absent; nutlets obovoid, reticulately ridged, pubescent or glabrous, attachment scar lateral, 0.2-0.5x as long as nutlet; endosperm scanty or absent.  2n =14, 20, 28, 38.  Seventeen species of dry habitats, ranging from southern Canada to Mexico, Florida, and the Bahamas.  Five sections are recognized: Calyx strongly zygomorphic, inverted in fruit: sect. Trichostema. Annual herbs; calyx actinomorphic: sect. Orthopodium Benth. Inflorescence densely lanate; leaves linear, revolute: sect. Chromocephalum F. H. Lewis. Not as above; corolla bright pink; stamens nearly straight: sect. Rhodanthum F. H. Lewis. Not as above; corolla violet; stamens arched: sect. Paniculatum F. H. Lewis.

Distribution

Native to:

73 Northwestern U.S.A.
74 North-Central U.S.A.
75 Northeastern U.S.A.
76 Southwestern U.S.A.
77 South-Central U.S.A.
78 Southeastern U.S.A.
79 Mexico

Synonyms

Isanthus Michx., Fl. Bor.-Amer. 2: 3 (1803).

Eplingia L.O.Williams, Fieldiana, Bot. 36(3): 18 (1973). 

Publication

Trichostema L., Sp. Pl. 2: 598 (1753); L., Gen. Pl. ed. 5: 260 (1754); Lewis, Brittonia 5: 276-303 (1945); Lewis & Rzedowski, Madroņo 25: 151-154 (1978).

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Image resource

Š Royal Botanic Gardens, Kew