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).Image resource
Š Royal Botanic Gardens, Kew