114 MILTONIA. 



Conlillcra, as far as tlic souitcs of tlie rivers Sinu and San Jurjc, in 

 the province of Antioquia, in North Colombia. Over this region it 

 occurs in greater or less quantity in isolated patches. Among the best- 

 known stations are the central Cordillera, between Frontino and 

 Sonson, on the Tavallones de Cali, the undulated plateau of Popayan, 

 and the western slopes of the volcauos of northern Ecuador. The 

 whole region in which Milfoil? a vexillaria grows is avcII defined and 

 similarly Ijoiuided. With one exception, the variety alhiccan which 

 occurs at 4,000 — 4,.500 feet elevation on the river Cuaiquer, the lower 

 and higher limits of Miltovia vexillana are almost everywhere about 

 4,750 and 6,500 feet above sea-level. The average mean tem|)erature of 

 the year Itetween these limits fluctuates between 16"5° — 19"5° C. (62° — 

 67° F.), that of the variety alhicam 20°— 21^ C. (68°— 70° F.) ; the 

 extreme daily range when the mornings are clear and the days bright 

 is from 12' C. (53° F.) mininuun, to 25° C. (77° F.) maximum. 

 Generally sjieaking, Mlltonia vexillaria is found isolated in places 

 intiueiK-eil by local climatic conditions, lieing most abundant at its 

 medium altitude : it always occurs on the borders of the denser 

 mountain forests which have below them either open or park-like 

 stretches covered with low bushes or coarse savannah grass, and above, 

 the extremely humid and almost impenetrable and luxuriant forests that 

 cover the Cordilleras at that altitude. The characteristic hygrometric 

 peculiarity of the whole region over which Miltonia vrxillaria is spread 

 is, that it is constant nearly throughout the year ; even in what is 

 called the dry season the air is only relatively less hiunid. The daily 

 changes in the weather may be thus summarised : — During the dry 

 season the day breaks clear, but soon after sunrise a thick mist settles 

 over the forest till about 10 a.m ; it then ascends higher, and the rays 

 of the sun begin with difficulty to penetrate it ; the air is then filled 

 with a bluish mist that shuts out the distant view. A light shower of 

 rain falls in the afternoon about 2 o'clock, which often continues till 

 evening, Avhen it gives place to a thick mist. During the rains there 

 is generally a light wind blowing towards the mountains from the lower 

 river valleys. In the rainy season the circumstances are nearly the 

 same, except that the rain is more copious, the drops heavier, and the 

 showers of longer duration. At times the rain is continuous for several 

 days in succession ; the atmosphere is then at the saturation point. 

 Of the varieties described above scarcely anything has been divulged 

 respecting their oi'igin. Herr Lehman n, indeed, states that rubella 

 is a geographical form first gathered by Wallis in 1876, and sub- 

 sequently by himself, but gives no locality ; Leopoldi and stwpenda 

 are both very distinct forms whose origin is unknown to us. The 

 colour variations or sub-varieties are innumerable, often gliding into 

 each other by insensible gradations so that it is almost futile to 



