406 Hill . — The Morphology and Seedling Structure of the 
in the leaves, whose small ovate, orbicular laminae are rather stout and 
fleshy and usually slightly concave. In a transverse section of a lamina of 
a mature leaf there is seen to be a narrow layer of water-storing tissue on the 
upper surface, consisting of the epidermis and a single row of hypodermal 
cells, and below this is a double palisade-layer of fairly long cells ; the rest 
of the leaf is composed of spongy mesophyll, the lowest layers of which 
contain no chlorophyll. Hydathodes, consisting of a protruding gland-cell 
with a basal cell, are sunk in deep pits, and are distributed chiefly over the 
lower surface of the lamina, though they occur on the petioles and inflor- 
escence-stalks as well. 
The petioles and inflorescence-stalks are short, stiff, and erect ; the 
latter are few flowered and are not much longer than the leaves (Figs. 2 6 and 
27, PI. XXIX). In old plants the bulbs are generally spherical, about 
10 mm. long by 12 mm. across, though in some cases they reach a length of 
18 mm. (Fig. 28) ; in general structure they are typical corms with a single 
median basal tuft of roots. 
This species was found in an exposed position on little damp ledges on 
a hillside above Copacabana, at the southern end of Lake Titicaca, some 
13,500 feet above sea-level, which no doubt accounts for its pronounced 
xerophytic characters. 
P. VERRUCULOSA SP. NOV., Dahlst., AND OTHER SPECIES. 
Very similar plants, at least as far as their external morphology is 
concerned, were collected on the exposed hillside of the hill of Sachshuaman, 
above Cuzco, some 12.000 feet above sea-level. 
Although no seedlings were obtained, it is clear that P. verruculosa , 
Dahlst. 1 , belongs to the group under discussion, and the structure of the 
fruit (F'ig. 29, PI. XXIX) proves it to be a new species allied to P .parvifolia, 
C. DC. The fruit is about 1*4 mm. long by i-i mm. broad, and contains 
a seed measuring about *7 mm. by *55 mm. 
The pittings in the pericarp wall are very much deeper than in P . par - 
vifolia , and the fruit has in consequence a much rougher appearance (cf. 
Fig. 18). In section the pericarp consists of five rows of cells ; the innermost 
layer, bounding the testa of the seed, is formed of fairly large, clear and 
tangentially elongated cells, and surrounding these are two layers of small, 
more or less isodiametric cells. Of the two outermost layers forming 
the outer wall of the fruit, the external is composed of long radially 
elongated and often curved cells with thick walls, which are arranged in 
groups. Between these groups deep pits occur, and four to six cells of the 
internal layer form a gland at the base of each pit (Fig. 29, g). The 
1 This species has been determined by Dr. Dahlstedt from my material, and his description will 
shortly be published. 
