Alfaroa guanacastensis
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| Alfaroa guanacastensis | ||||||||||||
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Alfaroa guanacastensis is aspecies of tree from the walnut family(Juglandaceae) endemic to Costa Rica .
features
Alfaroa guanacastensis is a monoecious tree up to 27 m high with a diameter of up to 90 cm at chest height . Buttress roots are small to large and reach up to 3 m on the trunk. The bark is whole or shed in small pieces. It is up to 1 cm thick, reddish brown on the surface, continuously pink on the inside or pink on the outside and orange on the inside. The buds and branches are bare.
The leaves are opposite and bare. The leaf stalks are 2 to 5 cm long, the rachis usually 4 to 16, rarely up to 22 cm. The 8 to 10 leaflets are opposite or almost so, with entire margins, symmetrical, flat to slightly rolled back and glabrous, with the exception of occasional hairs on the leaf base between the leaf vein and the edge. The leaflet stalks are 2 to 7 mm long.
The female inflorescences are terminal on this year's shoots, are stiff and upright with up to 45 flowers per ear . The male kittens stand in groups of 2 to 6 and form a contracted, terminal panicle on this year's shoots or they arise from axillary buds on previous year's shoots. Androgynous panicles are also found, with one to two pairs of opposite male catkins and one to four female flowers in a terminal catkin above.
The male flowers smell of gardenia and are sessile. They stand in a three-lobed bract that is short, broad and obtuse. The four flower segments are dome-shaped, each partially covering three of the total of 12 stamens . The pollen grains are almost triangular in polar view and have a diameter of 21.8 micrometers. The female flowers are petiolate. The three-lobed supporting sheet is fused with the bracts. The four calyx lobes extend over the stigma and form a chamber during flowering, but they can also be bent back. The stylus is short or missing, the stigma lobes are horseshoe-shaped.
The shape of the fruit is variable and ranges from spherical with 2.5 cm in diameter to oblong (3.8 × 1.7 cm). The calyx remains as a beak at the top. The bract-leaf flap is 8 to 10 mm in size and pressed against the nut. The shell is relatively thin at 3 mm, the surface is smooth, with slight longitudinal furrows and ribs. The nutshell is 1 to 2 mm thick and hard.
The first two leaves of the seedling, which appear in the open air, are variable, opposite or almost so, simple or compound, entire, rarely with a few small teeth. The next leaves are alternate, pinnate and with entire margins. Over time, the leaves become opposite.
Distribution and locations
Alfaroa guanacastensis is only known from the Cordillera de Guanacaste in Costa Rica , Guanacaste Province , among others from the volcanoes Orosi, Maravalles and Tenorio and the area around San Ramon at the southeast end of the Cordillera de Tilaran . It grows in the submontane rainforest at an altitude of 650 to 1000 m. It occurs on the lower wet slopes of the Caribbean-facing side, as well as in the area of passes and ridges where the moist air coming from the Pacific sweeps past.