220 MR. W. B. HEMSLEY ON THE 
In addition to the foregoing, some of the plants taken for 
perennials may be monocarpic, but of bienmial or two seasons’ 
duration, as many plants of this class form large tap-roots in 
which is stored during the first season the food required for the 
flowering and fruiting season. 
Meconopsis horridula, one of the most conspicuous and widely- 
spread plants of Tibet, probably flowers only once though of two 
seasons’ duration. 
Diuinvtive Prants. 
In more than one place stress has been laid on the fact that 
Tibetan plants generally are of small dimensions; but some of 
them are so exceedingly small as to merit attention on that 
account ; and it is among the annuals that some of the smallest 
are found, notably Pleurogyne brachyanthera, Gentiana Thonsoni, 
and G. aquatica, which are sometimes not more than an inch 
high with a solitary terminal flower. Among others of excep- 
tionally reduced propertions are: Ranunculus tricuspis, R. similis, 
R. involucratus, Anemone imbricata, Corydalis Boweri, Eutrena 
Przewalskii, Arenaria Littledalei, Saxifraga parva, and Sedum 
Przewalskii. So many others are small for their respective 
genera that it is sufficient to put the fact on record. But Iris 
Thoroldi, having narrow, grass-like leaves, rising at the most six 
inches above the ground, and solitary, yellow flowers, barely 
emerging from the ground, specially deserves mention as the 
miniature of its genus. Going back to the first of these 
diminutive plants, Ranunculus tricuspis; there are specimens 
of this at Kew from Mongolia, collected by Przewalski, and from 
Tibet, collected by Rockhill and Pike; therefore from very distant 
habitats; and the specimens all appear to have attained normal 
dimensions. Pike collected his specimens in moist soil, near a 
small stream, in about 82° and 34°, at an elevation of 17,000 ft. 
The largest specimen is less than three inches long, including the 
tap-root, which is not whole, having been broken off when 
removing the plant from the ground. It has about half-a- 
dozen stalked leaves with a three-lobed blade, about a quarter 
of an inch long, and one flower. Only the blade of the leaf 
appears above ground and that is spread out horizontally. The 
solitary flower, about a quarter of an inch in diameter, is scarcely 
rai-ed above the outspread leaves which encircle it. This 
interesting little plant is evidently a perennial, which propagates 
itself vegetatively by very short stolons. 
