DANIEL & TRIPP: LOUTERIDIUM : TAXONOMY, BIOLOGY, AND CONSERVATION 99 
[ca. 17°17’45.05”N, 099°28’17.54”W], 750 m, 19-1-1964 (fir), H. Kruse 1380 (holotype: ENCB- 
002790-shoots bearing flowers only-image seen; isotypes (shoots bearing flowers only): EAP!, 
ENCB-002789!, FCME!, MEXU!, MICH!, MO!, US!). 
Shrubs to trees to 4 m tall. Older (woody) stems irregularly fissured-striate, lenticellate, lack¬ 
ing trichomes; younger (herbaceous) stems quadrate-sulcate, glabrous (or with the surface rough¬ 
ened but lacking trichomes). Leaves seasonally deciduous, clustered at branch apices (and appear¬ 
ing quadrate at some nodes), petiolate, petioles 20-90 mm long, blades apparently subsucculent, 
lanceolate to ovate to elliptic, 82-260 mm long, 35-110 mm wide, 2-2.6 x longer than wide, 
(rounded to) acuminate at apex, cuneate to subattenuate at base, abaxial surface minutely glandu¬ 
lar-punctate (sometimes not evident) and sparsely pubescent (especially near base) with flexuose 
eglandular trichomes 0.2-0.7 mm long or trichomes absent on mature leaves, adaxial surface very 
sparsely pubescent (if at all) with similar trichomes, margin entire to subsinuate, sparsely ciliate 
with trichomes like those of abaxial surface. Inflorescence a terminal sessile or pedunculate thyrse 
to 303 mm long (including peduncle, if present, and excluding corollas), peduncle (if present) to 
52 (or more?) mm long, glandular-puberulent with glandular trichomes to 0.1 mm long, rachis 
pubescent with erect glandular trichomes 0.05-0.2 mm long; dichasia opposite, pedunculate, most¬ 
ly 1-3-flowered, to 50 (-70 in fruit) mm long (excluding corollas), dichasial peduncles 6-14 (-29 
in fruit) mm long, pubescent like rachis. Bracts caducous (not seen). Bracteoles caducous (not 
seen). Flowers pedicellate, pedicels 23-30 (-48 in fruit) mm long, pubescent like rachis. Calyx 
5-9 mm long, lobes fused for 1-3.5 mm at base, subheteromorphic, apparently subsucculent, abax- 
ially pubescent with erect to flexuose glandular trichomes 0.05-0.2 mm long, posterior lobe 
subconduplicate, broadly ovate to subtriangular, 3.5-4.5 mm long, 3^4.3 mm wide, sometimes 
smaller than lateral lobes, subacute to acute at apex, lateral lobes ovate to subtriangular, 4^4.8 mm 
long, 3-4 mm wide, acute at apex. Corolla green and maroon-purple, 35-39 mm long, externally 
puberulent with erect glandular trichomes to 0.1 mm long, tube 17-30 mm long, narrow proximal 
portion 4.5-9 mm long, 6-11 mm in diameter near midpoint, throat 11-20 mm long, 20-25 mm in 
diameter at mouth, lobes spreading to recurved, subtriangular to ovate, 10-13 mm long, 9-12 mm 
wide, rounded at apex. Stamens 4, 55-75 mm long, filaments glabrous (at least distally, proximal 
portion not seen), thecae 7.5-8 mm long; staminode (if present) not seen. Style 80-82 mm long, 
glabrous, stigma 2-lobed, lobes ± funnelform, 1.5 mm long, shape and width not determined. 
Capsule 38^47 mm long, 4.7-6 mm in diameter, pubescent throughout with erect glandular 
trichomes to 0.1 mm long, stipe 4 mm long. Seeds up to 24 per capsule, 4-4.5 mm long, 3^4 mm 
wide, surfaces minutely granulate to ± scurfy. 
Phenology.— Flowering: January; fruiting: January-March. Kruse 1380 noted that the flow¬ 
ers were “pronto caedizas,” possibly referring to their being soon deciduous during the day, and 
thus likely largely nocturnal. 
Distribution and habitat.— Western Mexico (central Guerrero; Fig. 8); plants occur on 
limestone slopes in tropical subdeciduous forests (selva mediana subcaducifolia) at elevations near 
750 m. 
Conservation. — Daniel (2017) discussed the rationale for and provided a preliminary 
conservation assessment of Data Deficient (DD) for L. rzedowskianum, which is known only from 
a single site. 
Illustrations. — Rzedowski (1973:53, fig. 4). 
Discussion. — Daniel (2017) discussed the necessity for validating this name, its typification, 
and the sole collection locality. 
Additional specimens examined.— MEXICO. Guerrero: Mpio. Chilpancingo, Rincon de 
