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PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 65, 28 Sept. 2018, No. 2 
to acute (distal leaves) to attenuate (proximal leaves) at base, surfaces glabrous, margin entire and 
sometimes with inconspicuous marginal swellings/encrustations. Inflorescence a terminal (raceme 
to) racemose thyrse to thyrse to 580 mm long (including peduncle and excluding corollas), pedun¬ 
cle to 240 mm long, glabrous, rachis glabrous; dichasia expanded or somet im es modified by very 
short expansion between pairs of succeeding flowers with the congested dichasial axis becoming a 
± linear racemelike lateral short-shoot to 10 mm long, opposite, sessile to pedunculate, (1-) many- 
flowered, to 70 mm long (excluding corollas), dichasial peduncles (if present) to 24 mm long, 
glabrous. Bracts caducous, subfoliose, ovate to lanceolate, 18-52 mm long, 3.5-18 mm wide, 
reduced in size toward apex, abaxially glabrous. Bracteoles caducous, triangular, 2-7 mm long, 
1.5-2.5 mm wide, abaxially glabrous. Flowers pedicellate, pedicels 30^43 mm long, glabrous. 
Calyx 18-26 (-29 in fruit) mm long, lobes fused at base for 1-1.5 mm, subheteromorphic, sub¬ 
succulent, linear to lance-linear, 15-25 mm long, 3-5 mm wide, (subrounded) to acute at apex, 
abaxially glandular-punctate (punctations to 0.1 mm in diameter, sometimes sparse) but lacking 
elongate trichomes, posterior lobe subplanar to subconduplicate, 15-23 mm long, equal to or short¬ 
er than lateral lobes, 3-5 mm wide, lateral lobes 17-25 mm long, 3.2-5 mm wide, all lobes (sub¬ 
rounded to) acute at apex. Corolla light green or greenish yellow with lobes usually becoming 
slightly maroon-tinged and darker maroon at distal tips with age, 35^40 mm long, externally 
glabrous, tube 21-23 mm long, narrow proximal portion 5-8 mm long, 6-11 mm in diameter near 
midpoint, throat 14-17 mm long, 19-23 mm in diameter at mouth, lobes recurved to recoiled, 
oblong to ovate-elliptic, 12-14.5 mm long, 8.5-10.5 mm wide, rounded and bifid at apex. Stamens 
4, 55-77 mm long, distally glabrous, pubescent near base with eglandular trichomes, thecae 
yellowish green, 6.5-9.5 mm long; staminode 1, ± triangular, 0.1-1.5 mm long. Style 60-67 mm 
long, glabrous, stigma unequally 2-lobed and ± obliquely funnelform, 1.5-2 mm long, lobes ± 
elliptic, 1-1.5 mm long, 0.6-1 mm wide. Capsule (20-) 23-26 mm long, 4-6 mm in diameter, 
glabrous, stipe 1.5-2 mm long. Seeds up to 16 per capsule, 4^1.5 mm long, 3-4 mm wide, surfaces 
with subconic to low rounded protrusions or becoming smooth. 
Phenology. — Flowering: January-March; fruiting: February-March, June. In the two pop¬ 
ulations of this species observed for ca. one hour each, floral buds were present on the plants at 
both sites during daylight hours (morning for Daniel 8294 and afternoon for Daniel & Butterwick 
5905), and mature fallen flowers were present on the ground at one site {Daniel 8294). Likewise, 
Brewer et al. 7176 notes that the corollas fall in the morning. 
Distribution and habitat.— East-central Belize (Belize, Cayo; Fig. 10); plants occur on 
steep limestone slopes in evergreen seasonal forests (tropical evergreen seasonal broadleaf lowland 
forest fide Meerman and Sabido 2001) at elevations from 10 to 120 m. 
Illustrations. — Figure 12; Leonard (1936:197, fig. 1). 
Conservation. — Daniel (1997) noted that the population at the type locality had been 
destroyed by quarrying activities, but that other populations had been located on several of the 
small, isolated, and steep limestone hills in the southern portion of the coastal plain in Belize 
District. Louteridium chartaceum has since (i.e., in 2005) been located in Cayo District, as well. 
Plants occur in at least three protected areas, and the species’ EOO (189 km 2 ) includes a portion of 
another one. Ecologist and botanist Steven Brewer (in litt., 14 May 2018) indicates that the species 
“is co mm on though not abundant on ridge-tops and exposed limestone along the north side of the 
Maya Mountains in Cayo and Belize districts.” Brewer (in litt., 22 May 2018) also notes that in this 
region, potential threats to all of the limestone forests include land conversion via agriculture (both 
in and around protected areas), encroachment or settlement in protected areas, and fire (either 
natural or “escaping” flames from regular burning used to clear nearby agricultural fields or bush). 
