Hypnella ambrosia (Bryopsida: Hookeriaceae), a New Species from Bolivia Marko Lewis Hert )ario Nacional de Bolivia, Casilla 10077, La Paz, Bolivia Bruce Allen Missouri Botanical Garden, P.O. Box 299, St. Louis, Missouri 63166-0299, U.S.A. Abstract. The existence of a Hypnella species the basal cell quadrate, red-brown, the upper cell (Hypnella ambrosia, sp. nov.) with short marginal swollen, oblong, hyaline; pseudoparaphyllia absent; leaf cells, cells with walls projecting at the upper paraphyllia absent; irregularly branched, branches ends, occasionally doubly serrate leaf margins, cos¬ ± parallel. Leaves complanate wet or dry, erect tae serrate above, and costal tips strongly projecting when dry, spreading to wide-spreading when wet, as spines is suggestive of a close generic relationship lanceolate to oblong-lanceolate, gradually narrowed to Hookeriopsis sensu lato. to long, slender, flexuose acumina, 1.0-1.8 mm x 0.15-0.30 mm, margins weakly serrate at middle, Cerro Amboro, within Amboro National Park, is strongly serrate at apex, teeth mostly single, oc¬ an area with deep sandstone canyons lying between casionally double, each tooth often ending in a pa¬ the high tropical Andes of the Cordillera Real, the pilla; costae double, ± parallel, projecting as 1-2- sub-Andean ranges of Chuquisaca and Tarija, and celled spines near the base of the acumen, with multi- the sandstone ranges of the Chiquitos. Clusia shrub- celled serrations along the upper margins, serrations lands, grading into isolated grasslands, dominate the often ending in 1 or 2 papillae, in cross section upper slopes of Cerro Amboro. The lower canyons rounded, with 3-4 layers of homogeneous, uniform¬ are densely forested, and isolated riverine forests ly thick-walled cells; leaf cells thin-walled through¬ follow the deeper canyons nearly to the summit. out, at insertion reddish or hyaline, rectangular, 30- During a botanical expedition to the summit of Cerro 40 p.m x 6-8 /am, basal cells long rectangular, 25- Amboro (September 1990), the senior author col¬ 47 /am x 5-6 /um, upper cells elongate fusiform to lected extensively in the upper canyon forests where vermicular, 23 53 /am x 6-8 /am, upper marginal an unusual species was encountered along rills and cells somewhat wider and shorter than laminal cells, creeks from 900 to 1,250 m. The species has fea¬ cells with single papillae variously placed over the tures found in Hypnella, Hookeriopsis sensu lato, surface and often projecting at the upper cell ends, and Callicostella, but the presence of pluripapillose or 2-4 papillae scattered, at times in irregular hor¬ cells indicates the first-named genus. This taxon is izontal rows, over the surface of the cell lumina. unlike any known species of Hypnella. Sporophytes unknown. Hypnella ambrosia M. Lewis & B. Allen, sp. nov. Paratypes. Bolivia. Santa cruz: Prov. Ichilo, Cerro Amboro, ca. 35 km S of Buena Vista in Parque Nacional TYPE: Bolivia. Santa Cruz: Prov. Ichilo, Cerro de Amboro, 17°45'S, 63°39'W, Lewis 37823, 37859, Amboro, between upper Rio Isama and summit, 37860 (all LPB, MO). ca. 35 km S of Buena Vista, Parque Nacional de Amboro, Cerro Amboro, 17°45'S, 63°39'W, Hypnella ambrosia is common on the banks of ca. 900 m, Lewis 37820 (holotype, LPB; is¬ creeks and rills in the upper canyons of Cerro Am¬ otypes, MO, NY). Figures 1-7. boro between 900 and 1,250 m. It appears to be semi-aquatic and is especially abundant in areas near Species nova Hypnellae piliferae proxima foliis gra- creek high-water levels and seepy zones near springs datim angustatis, acuminatis, longis differt. and rills. It grows on soil and bare rock. Its soft, Plants in thin green mats, occasionally purple pale green, occasionally red-tinted, flattened mats tinted. Stems red, 2-3 cm long, 0.1-0.15 cm wide, make it a distinctive element of the upper canyon central strand absent, epidermal cells somewhat dif¬ forests of Amboro. ferentiated, thin-walled, enlarged, at times appearing Hypnella ambrosia is similar to Callicostella in as a hyaloderm, not fluted; axillary hairs 2-celled, having some cells with single papillae; however, its Novon 2: 355 357. 1992. 356 Novon Figures 1-7. Hypnella ambrosia M. Lewis & It. Allen. —1. Habit. —2. Median leaf cells. —3. Marginal leaf cells below apex. —4. Apex of costa. —5. Leaves. —6. Stem cross section. —7. Marginal leaf cells. Figures 1, 4- 7 from holotype; Figures 2, 3 from Lewis 37860. Top scale bar = 40 gm, leaf cells; middle scale bar = 400 ^m, leaves and stem cross section; bottom scale bar = 1 mm, habit. Volume 2, Number 4 Lewis & Allen 357 1992 Hypnella ambrosia long, vermicular, frequently pluripapillose leaf cells 3. Marginal leaf cells short, broadly rectangular; remove it from that genus. Long leaf cells (occa¬ costae serrate above, strongly projecting by two or more cells . sionally with projecting end-walls), short, broad, dou¬ . H. ambrosia M. Lewis & B. Allen ble-toothed marginal cells, and strongly serrate cos¬ 4(1). Leaves ecostate; leaf cells all papillose or en¬ tae that may end in distinct spines are all features tirely to partly smooth . of Hookeriopsis sensu lato. The long, pluripapillose .H. guayanensis B. Allen & Buck in Buck leaf cells of this species place it in Hypnella. Hyp¬ 4. Leaves costate; nearly all leaf cells papillose . 5 nella and Hookeriopsis sensu lato are closely re¬ 5(4). Leaves long-acute, apex serrate by projecting lated, as demonstrated by several shared features. cell wall ends, ± bordered by long narrow ± For example, leaves ol Hypnella pilifera (Hook. & smooth cells .//. punctata Broth. Wils.) A. Jaeger occasionally have weakly spined 5. Leaves subacute or obtuse, apex serrulate due to lateral, projecting papillae, not bordered ... 6 costae, and the marginal cells of Hypnella leptor- 6(5). Leaf papillae mostly multifid; leaves obtuse, rhyncha (Hook. & Grev.) A. Jaeger frequently have not apiculate, 0.5-1.0 x 0.2-0.4 mm; mo- projecting ends. Hypnella ambrosia is close to II. noicous; exostome furrowed; capsule neck tu¬ pilifera (Hook & Wils.) A. Jaeger. The latter species bercular to scabrous . has oblong leaves, often wider above the middle, . H. pallescens (Hook.) A. Jaeger 6. Leaf papillae simple; leaves subacute, apicu¬ that are abruptly narrowed to the acumen. Although late, 1.0-1.2 x 0.3-0.6 mm; dioicous; ex¬ the lower marginal leaf cells in //. pilifera are long ostome not furrowed; capsule neck papillose and narrow, the marginal cells in the upper one- . H. diversifolia (Mitt.) A. Jaeger third can be short and broad. There are now seven Acknowledgments. The senior author thanks species in Hypnella (Crosby et al., 1985; Allen, Bobin Clark for the opportunity to participate in the 1986; Buck, 1990). They are separated in the fol¬ expedition to Amboro, and the National Geographic lowing key. Society and the Missouri Botanical Garden for fi¬ nancial support. Key to the Species of Hypnella 1. Leaves long acuminate, subpiliferous or pili¬ Literature Cited ferous . 2 Allen, B. H. 1986. The taxonomic status of Hypnella 1. Leaves long-acute, subacute or obtuse . 4 punctata. Bryologist 89: 224-226. 2(1). Leaves rounded at the apex, abruptly pilifer¬ Buck, W. R. 1990. Contributions to the moss flora of ous . H. pilfer (Hook. & Wils.) A. Jaeger Guyana. Mem. New York Bot. Card. 64: 184-196. 2. Leaves gradually and evenly long acuminate Crosby, M. R„ B. H. Allen & R. E. Magill. 1985. A to a piliferous apex . 3 review of the moss genus Hypnella. Bryologist 88: 3(2). Marginal leaf cells long, narrowly fusiform; 121-129. costae smooth above, not or very weakly pro¬ jecting by a single cell . . . . H. leptorrhyncha (Hook. & Grev.) A. Jaeger