Failure of reproduction is hypothesized as being a main reason for the formation of upper tree lines but there is, as yet, little supportive evidence of such. This study investigates the effects of experimental sowing, canopy cover and litter depth on seedling emergence and survival of Polylepis incana and Polylepis pauta at the upper distribution limit of the species in the Páramo de Papallacta, central Ecuador. We established 18 study plots located in the interior, at the edge and at the exterior of closed forests at the upper tree line and analysed seedling dynamics for 1 y following experimental sowing with four different litter treatments. For both species, seedling numbers were significantly higher in the forest interior than outside, and higher in the treatments with the litter layer removed. In P. pauta, sowing significantly increased seedling number, which was more pronounced within and at the edge of the forest than outside. In contrast, there was no impact of sowing on seedling emergence in P. incana. First-year seedling survival and mean growth rate per month were low in both species. Log-linear models did not reveal significant interactions between survival and canopy cover or litter removal. Our data show that seedling recruitment is limited at the upper tree line – presumably due to extreme climatic conditions – which indicates the importance of constraints in sexual regeneration for tree-line formation in central Ecuador.

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A new species, Cedrela domatifolia, is described. It is characterized by the leaves of 55–80 cm long, leaflets 10–15 pairs, this oblong-lanceolate, 15–25 cm long × 4–8 cm wide, with prominent and inflated domatium on the axes of the secondary veins on the underside; calyx shortly cupuliform, 2.3–2.5 mm long, 5-lobed, one side (in open flower, not in bud) split down to the base; corolla purple-reddish with the margin and apex cream, and bearded inside. The new species is a tree that reaches 40 m in height and is only known from the eastern slopes of Ecuador, between 800 and 1100 m approximately. It grows exclusively on black laminar rocks, slate type, and has a strong and unpleasant smell of garlic, more noticeable than in other species of the genus. The most related species is C. nebulosa, but with smaller leaflets without domatium. The distribution area of the first one is enclosed within the second.

A case of an intracerebral "primary" arachnoidal cyst of the left fronto-parietal region is reported. No communication with the ventricular system or with subarachnoidal space was found at the first surgical procedure. It contained genuine choroid plexus and clinically behaved as an expansive intracranial mass.

A case of an unusual congenital intramedullary tumor of the spinal cord is reported. A paraplegic 11-day-old boy with hypotonia and atrophy of the abdominal and lower-extremity muscles showed a complete myelographic block between T-5 and T-8. Surgical exploration disclosed an elongated tumor mass within the spinal cord, that blended with the surrounding nervous-system tissue. Light and electron microscopy showed that the tumor was composed of intermingled well differentiated astrocytes and fibroblasts. These two cell types often were surrounded by the same basal lamina. There were no intercellular junctions. Gliofibrils were abundant, and the interstitial spaces contained abundant collagen and reticulin fibers. There were no histological signs of malignancy. We conclude that this is a case of prenatally arising gliofibroma.