DANIEL & TRIPP: LOUTERIDIUM : TAXONOMY, BIOLOGY, AND CONSERVATION 79 
On a single flower of Daniel et al. 11894cv grown in San Francisco, corolla lobes began to 
separate at 15:50 and the corolla was fully open (lobes spreading 90° with respect to the throat or 
reflexed) with the stamens and style fully exserted by 16:15. By 18:00, all corolla lobes were at 
least partially recoiled. At 23:00, 6.5 pi of nectar was encountered in the nectar chamber, and the 
stigma was dusted with pollen from the anthers. At 07:15 the next day, 72.1 pi of nectar was recov¬ 
ered from the nectar chamber. The corolla abscised and fell from the persisting flower at 07:45. 
Thus, the corolla of the pollinated flower persisted for ca. 16 hours. 
Distribution and habitat.— Southern Mexico (Oaxaca; Fig. 8) in the Sierra Madre del Sur 
and the Isthmus of Tehuantepec; plants occur on limestone (often karstic) slopes of streams in trop¬ 
ical deciduous forests and tropical subdeciduous forests at elevations from 600 to 750 m. 
Illustrations. — Figure 2F-L; Daniel (2017:143, fig. 8). 
Conservation. — A discussion and preliminary conservation assessment of Endangered (En) 
was proposed for this species (Bl, a, b; IUCN 2017) by Daniel (2017). 
Discussion. — Louteridium dendropilosum is unique among congeners by its dendritic tri- 
chomes, which are present on both vegetative and reproductive organs. Trichomes of other species 
may consist of one or more cells and be either glandular or eglandular, but they are not branched. 
Bracts and bracteoles are caducous prior to maturation of the flowers associated with them; thus, 
they are rarely encountered and are not present on any of the wild-collected specimens. The data 
on their shape, size, and pubescence noted above were taken just prior to their dehiscence from the 
young inflorescence of a cultivated plant {Daniel et al. 11894cv). 
Additional specimens examined.— MEXICO. Oaxaca: Distr. Pochutla, Mpio. San Miguel 
del Puerto, Arroyo Arena, ca. 100 m downstream from jet. Rio Laja, ca. 3 km SE of Rancho Dioon 
toward Xadani, 15°58 , 51.33”N, 096° 05’53.91”W, T. Daniel, et al 11894 (CAS, MEXU), 12187 
(CAS, MEXU), cultivated plants of 11894 grown from seeds in San Francisco, California, 11894cv 
(CAS); Mpio. El Barrio, 9 km N [sic] de El Barrio, Cerro Palmasola, antena microondas [ca. 
16°44 , 32.52”N, 095°05’36.04”W], R. Fernandez N. 4189 (IEB, NY); Distr. Pochutla, Mpio. San 
Miguel del Puerto, Arroyo Arena, 15°58’39.7”N, 096°05’54.9”W, J. Pascual 1396 (MEXU, 
SERO, TEX); Distr. Pochutla, Mpio. San Miguel del Puerto, 300 m de la terraceria sobre la vere- 
da rumbo Rio la Laja, 15 0 58’49.9”N, 096°06’6.9”W, A. Saynes V et al. 3831 (MEXU, SERO); 
Distr. Juchitan, Mpio. El Barrio, parte alta del Cerro Palmasola, junto a la antena de microondas 
[ca. 16°44’32.52”N, 095°5’36.04”W], S. Zamudio R. 6352 (CAS, IEB). 
5. Louteridium donnell-smithii S. Watson, Proc. Amer. Acad. Arts 23:284. 1888. Type.— 
GUATEMALA. Alta Verapaz: Pansamala, 3800 ft., V-1887 (fir, frt), H. von Tiirckheim 856 (holo- 
type: GH-00094124-images seen; see discussion). 
Shrubs or trees to 12 m tall, terrestrial or epipetric. Older (woody) stems subquadrate to 
quadrate, irregularly striate-fissured, pubescent or glabrate; younger (herbaceous) stems quadrate 
to quadrate-sulcate, densely pubescent with erect to flexuose eglandular trichomes to 2 mm long 
(distal 1 or several intemodes sometimes with glandular trichomes as well). Leaves not all season¬ 
ally deciduous, evenly distributed on young shoots, petiolate, petioles to 190 mm long, blades 
membranaceous, ovate to broadly ovate to cordate, 140^465 mm long, 85-316 mm wide, 1-2 x 
longer than wide, acuminate at apex, acute to rounded to cordate at base, surfaces densely pubes¬ 
cent with cauline type trichomes, margin crenate-dentate with rounded (to acute) teeth up to 2 mm 
long. Inflorescence a terminal pedunculate raceme to thyrse to 450 mm long (including peduncles 
and excluding corollas), peduncle to 250 mm long, pubescent with flexuose glandular and eglan¬ 
dular trichomes to 2.8 mm long (viscid), rachis viscid; dichasia opposite, sessile or pedunculate, 
(1-) 3-5 (-many)-flowered, to 130 (-185) mm long (excluding corollas), dichasial peduncles to 
