With these plants from the temperate zone are mixed the far outliers
of the tropical genera--orchids, begonias, and others--whose ascent
to these high regions has been favoured by the great summer heat
and moisture.

We are now in the region of the primulas for which (besides its
orchids and rhododendrons) Sikkim is famous. Sikkim may indeed
be called the headquarters of the Indian primroses, and many species
are found there which appear to occur nowhere else. There are from
thirty to forty species, the majority growing at altitudes from 12,000
to 15,000 feet, two or three only being found below 10,000 feet, and
two or three as high as 16,000 to 17,000 feet. The best known is the
_ Primula sikkimensis,_ which grows well in England and resembles
a gigantic cowslip. It thrills us to see it growing in golden masses in
the high valleys in wet boggy places--though the precise colour may
be better described as lemon-yellow rather than gold.

The prevailing colour of the primulas is purple, but white, yellow,
blue, and pink are also found. The _P. denticulata_ has purple to
bright sapphire blue flowers, and great stretches of country are
almost blue with the lovely heads of this primrose. Miles of country
can be seen literally covered with _P. obtusifolia,_ which has purple
flowers and a strong metallic smell. _P. Kingii_ is a lovely plant
with flowers of such a dark claret colour that they are almost black.
And perhaps the most striking primula is _P. Elwesiana,_ with large
solitary deflexed purple flowers.

Poppies also are a feature of the Sikkim vegetation. Near the huts
the people cultivate a majestic species near _Menconopsis
simplicifolia,_ but it grows in dense clusters 2 or 3 feet high. The
flowers vary in diameter from 5 to 7 inches, and are an intensely
vivid blue on opening, though they change before fading into purple.
_M. simplicifolia_ itself is also found at altitudes from 12,000 to
15,000 feet--a clear light blue species of special beauty, growing
as a single flower on a single stem, and now to be seen at
both Edinburgh and Kew. Another beautiful poppy is the _M.
nepalensis,_ which grows in the central dampest regions of Sikkim
at elevations of 10,000 to 11,000 feet and resembles a miniature
hollyhock, the flowers being of a pale golden or sulphur-yellow, 2 or
3 inches in diameter and several on a stalk.

As Tangu is approached the valley expands into broad grassy flats,
and here at about 13,000 feet th