Lycopersicon spp. as illustrated by Ocros (Ochoa, No. 1410 and 1412) and Gorgor (Urbizagástegui,
DHUNA 1340); besides, the peculiarities shown by the Fortaleza collections of L. peruvianum warrant a
study of its relations with nearby material.
13. Watershed: Supe-Huaura
(Table 15, fig. 6)
Observations on Lycopersicon spp.
Although Lycopersicon peruvianum is found in the lower Supe, it is notable that the lower Huaura
(up to 1200 m) lacks this species. This may be an example of the observation that Lycopersicon species
as weeds are poor competitors and soon disappear as modern agricultural techniques enter a valley. In
this case though it happens that L. pimpinellifolium has still been collected recently in the lower,
intensively developed agricultural area. The upper L. peruvianum samples are fairly recent, but they
seem to belong to the typical coastal form that prevails from here to the Rímac.
Several sites of small populations of L. hirsutum var. typicum have been detected, but only one seed
collection is available (Navan, LA 1378). The relation of this population to other watersheds is yet to be
determined. The rather sparse distribution of plants of this species is typical in all the area south to
Pisco, its southernmost limit. One has to go into the nearby "quebradas" with more moist conditions to
find individual specimens which usually are of great size.
The collections of Solanum pennellii near Sayan (DHUNA 1001, LA 1376) were on a mountain side
where this was nearly the dominant species in 1972, an especially rainy year at this altitude. This
dominance is highly unusual since S. pennellii is very sparsely distributed in normal situations. The
site's other peculiarity was the presence of L. pimpinellifolium as a sympatric plant. This situation is
unique in the experience of the authors.
14. General Description of the Watersheds from Huaura to Rímac
(fig. 6)
A general description for the Huaura, Huaral-Chancay, Chillón and Rímac watersheds is given since
the agricultural and ecological characteristics are similar. In all cases the delta and middle drainages
are fairly large, while above 1200 m the valleys narrow conspicuously to canyons, and above 2200 m a
typical "sierra" situation begins. Rainfall patterns can be divided into three types: 1) foggy mist
producing "loma" growth from 200 to 800 m; 2) dry sunny desert from 1100-1800; and 3) temperate
conditions with moderate rainfall and vegetative cover subject to more overcast.
The main crops are cotton (Tanguis variety), coastal corn hybrids, vegetable crops, winter potatoes
(April through October), oranges and mandarins in the lower area; temperate fruit trees in the middle
valley; and small grains, corn varieties, and potatoes from October through April.
15. Lomas Between the Huaura and Huaral Watersheds
(Table 16, fig. 6)
The "lomas" of this area are some of the most conspicuous and common of the central coast of Perú.
During some years they develop an annual vegetation that can carry up to 10,000 head of livestock
(cattle, goats, and horses). L. peruvianum is usually found in the rocky crevises on the sides of the hills,
while Solanum pennellii appears only in the dry washes in the years when summer rains are frequent
(e.g. 1972).
16. Watershed: Huaral-Chancay; and Lomas between Chancay and Chillón Watersheds
(Table 17, fig. 6)
In this watershed the drainage is divided into two forks. The southern one is a large "quebrada" in
that has water during three to four months each year and some permanent agriculture in the form of
peach and apple orchards above 500 m. No L. hirsutum apparently
appears here because it is very dry up to the altitude where it joins with the northern fork.
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