Epiphytic shrub 1-3 m tall;  stem base to 2.5 cm in diam.;  mature branches terete to subterete, smooth or minutely striate, glabrous, 6-7 mm in diam.;  bark brown when fresh, but drying yellowish-, grayish-, or reddish-brown;  twigs subterete to bluntly angled, minutely striate, glabrous, reddish-brown.  Leaves lanceolate to elliptic-, oblong-, or ovate-lanceolate, rarely oblanceolate or ovate, (3-)8-15(-18) x 1-5(-6) cm, basally rounded, obtuse, broadly cuneate, or rarely subtruncate or subcordate, apically acuminate, glabrous or rarely with a few hairs at base of midrib on upper surface;  (3-)5(-7)-plinerved rarely more or less bullate, all nerves impressed above or rarely veinlets and outer pair of lateral nerves raised, midrib raised and prominent beneath, lateral nerves raised and prominent to obscure beneath, veinlets slightly raised and usually obscure beneath, or midrib raised and thickened through proximal 1-7.5 cm otherwise plane to impressed above and raised beneath, with lateral nerves arising from 1-2.5 cm above base and impressed, or only inner pair impressed then outer 1-2 pairs raised;  petioles terete often flattened adaxially, rugose, (4-)6-15 mm long and (0.7-)1-2(-3.2) mm in diam, glabrous.  Inflorescence (7-)11-20(-30)-flowered cylindric to fusiform in bud;  rachis long-tapering, cylindric, bluntly angled, minutely striate, viscid, glabrous, 3-8(-9) cm long and (1.7-)2-5 mm in diam., pink to pinkish-white when fresh;  floral bracts rarely translucent when dry, smooth or reddish-papillate abaxially, oblong to oblanceolate, rarely obovate or somewhat spatulate, 20-40(-50) x 10-20 mm, basally narrowed and truncate, apically rounded to acute, glabrous, deep violet or lavender- to maroonish-purple, often appearing black;  pedicels swollen distally, striate or ribbed, glabrous, (6-)9-13(-16) mm long and 0.7-1(-1.5) mm in diam., pink to pinkish-white when fresh;  bracteoles located at base or just below middle of pedicel, lanceolate to linear-lanceolate rarely ovate, 1-4(-5.5) x 0.5-1(-2) mm, basally truncate or slightly auriculate, apically acuminate and glandular-callose in distal 1/3-1/2, purplish-pink when fresh but with glandular portion often appearing green.  Flowers:  calyx glabrous, 5.5-11(-13.5) mm long;  hypanthium cylindric, coarsely 10-ribbed, (2-)2.5-4(-5.5) mm long and (2.5-)3-6(-6.5) mm in diam. across base, apophysate and deeply 5-lobed basally with lobes straight or flaring outward and extending well below articulation;  limb cylindric or somewhat spreading, weakly ribbed or minutely papillate, 3-8 mm long;  lobes triangular, 1-2(-2.5) mm long and 2-2.5  mm broad, erect after anthesis, glandular-callose without, dark reddish-purple or green;  sinuses obtuse to broadly rounded;  corolla slightly constricted basally, narrowed to throat, sometimes translucent when dry, pilose with short white trichomes over entire length or only in distal half, 20-38(-45) mm long and 5-8 mm in diam., tube whitish-purple at constrictd base, purple to dark purple or lavender above, limb and lobes pale purple, lobes oblong, obtuse, 1.5-2 mm long, strongly reflexed at anthesis;  stamens 19-39 mm long;  filaments subglabrous or moderately pilose distally, or short ones sometimes glabrous, alternately 3.5-6 mm and 7-14.5 mm long;  anthers alternately 18-35.5 mm and 13-27.5 mm long;  thecae 6-13.5 mm long;  style 21-46 mm long.  Mature berry not seen.

    Distribution (Map).  Central Costa Rica eastwards to Coclé Prov. (possibly Colón), Panama, at elevations of (150-)400-2500 m.
 

 Key to Varieties of Cavendishia atroviolacea

1.  Corolla (23-)30-38(-45) mm long; midrib of leaves inconspicuously raised through proximal
     1-2  cm; bracteoles located at or near base of pedicels;  central Costa Rica to Chiriquí,
     Panama ................................................................................................ var. atroviolacea.
1.  Corolla 18-21 mm long; midrib of leaves raised through proximal 3-7.5 cm (proximal
     1/3-1/2 leaf length);  bracteoles located just below middle of  pedicel;  central Panama
     (Coclé and ?Colón Provs.) .......................................................................... var. folsomii.
 

Cavendishia atroviolacea Luteyn var. atroviolacea.  Images:  Habit. Flowers.

    Leaves lanceolate to lance-elliptic, rarely oblanceolate or ovate, basally rounded, obtuse, cuneate or rarely subtruncate, rarely more or less bullate;  midrib inconspicuously raised through proximal 1-2 cm;  petioles (4-)6-15 mm long and (0.7-)1-2(-2.5) mm diam.  Rachis 2-5 mm diam,;  floral bracts (2-)2.5-4(-5) cm long, deep violet or maroonish-purple;  bracteoles located at or near base of pedicels, 2-4(-5.5) mm long.  Flowers:  calyx (6-)7-11(-13.5) mm long;  limb (3.5-)5-8 mm long;  corolla (23-)30-38(-45) mm long.

    Distribution (Map).  W Panama and adjacent E Costa Rica, in undisturbed cloud forest, wet forest, along streambanks, and in remnant trees in pastured areas, at elevations of 400-2500 m.    The following specimen appears to be a hybrid between C. callista and C. atroviolacea: COSTA RICA. Cartago-San José border: 2.5 km N of La Sierra at km 42 along Panamerican Hwy., 1900 m, 23 Jul 1980 (fl), Wilbur 29558 (DUKE).
 

Cavendishia atroviolacea Luteyn var. folsomii Luteyn, Fl. Neotrop. Monogr. 35:  268.  1983.  Type.  Panama.  Coclé: 7 km N of El Copé, around sawmill at Alto de Calvario, 800-850 m, 28 May 1980 (fl), Folsom & Mauseth 7863 (holotype, NY, photo NY neg. 10862; isotype, TEX).

    Leaves ovate- to oblong-lanceolate, or oblong-elliptic, basally rounded to subcordate;  midrib conspicuously raised through proximal 3-7.5 cm (proximal 1/3-1/2 leaf length);  petioles 7-10 mm long and 2-3.2 mm diam.  Rachis 1.7-2.7 mm diam.;  floral bracts 2-2.5 cm long, lavender to purple-lavender;  bracteoles located just below middle of pedicels, 1-1.5 mm long.  Flowers:  calyx 5.5-8.5 mm long;  limb 3-5.2 mm long;  corolla 18-21 mm long.

     Distribution (Map).  Endemic to Panama, in wet montane cloud forest, at elevations of (150-?)600-850 m.  This variety should be considered Rare and endangered.