PEOF. H. M. WAED AND MISS E. DALE ON CEATEROSTIGMA PUMILUM. 347 



(PL XXXV. fig. 22). Some of these spaces are mere points, others are so large that the 

 cells arc attached to one another, laterally, by very small surfaces. 



Erom the underside of the leaf, through about half or two-thirds of its entire thickness, 

 the spaces are lined with red granules. The extreme irregularity in the size and form of 

 the spaces in the leaf is shown in PI. XXXV. fig. 22. 



In a longitudinal section the cells appear in rows, which in some parts are in contact, 

 but in others separated by spaces of variable Avidth, and tapering to a point wliere the 

 cells of adjacent rows are still united. As in the transverse section, the spaces vary 

 greatly in size and form, some appearing as small lenticular slits. 



Transverse Section of the Lamina. — The red colour is absent from the upper part of 

 the leaf, which in section differs little from the ordinary bi-facial type (PI. XXXV. fig. 21). 



On the upper side the epidermis consists of larger cells than on the lower. Storaata 

 and glands are present on both surfaces, but they are more numerous on the under side. 

 The palisade parenchyma consists of about four rows of cells, which are only slightly 

 elongated. The cells of the spongy parenchyma are rouoded, and connected with one 

 another by elongated processes, bridging over the intercellular spaces. 



A surface view of the epidermis shows the stomata and the glands. Seen from above 

 the epidermal cells appear rounded atid have undulating walls. The stomata are of the 

 usual type (PI. XXXV. fig. 23). Round the glands the epidermal cells are somewhat 

 pyriform, with their narrow ends near the gland and their broad ends directed away 

 from it, so that they form a kind of rosette. The reason of this arrangement is that the 

 glands are sunk into pits. It is these pits which cause the punctate appearance of the 

 leaves to which reference has already been made (p. 344). The glands themselves 

 (PL XXXV. fig. 24) show a circular head, sometimes divided by one or two cross-walls 

 into two or four smaller cells, containing dense granular protoplasm. 



In vertical section (PL XXXV. fig. 25) the glands are almost identical in appearance 

 with the liydathodes of P?'/?tr nigrum, described and figured by Haberlandt (' Physio- 

 logische Pflanzenanatomie,' 2nd edition, p. 420) and which also occur in depressions in 

 the leaves. They are divided into three parts, called by Haberlandt the head, the stalk, 

 and the foot. According to Haberlandt, the protoplasmic head functions as a peculiar 

 water-gland. The stalk represents the mechanical apparatus of the whole organ, as it is 

 provided with a thick ring of cellulose, which keeps a passage for the water always 

 open and of a uniform diameter. The foot, which connects the gland with the adjoining 

 epidermal cells and with the underlying tissue, is usually thin-walled. We liave been 

 unable to discover, in any of the glands of Craterosiigma pumilum which we have 

 examined, the ring of cellulose which Haberlandt describes and which was distinctly 

 visible in the stalk-cell of the hydathodes of Flper nigrum, in sections which were cut 

 for the sake of comparison with Craterosiigma. 



Whether the gland acts as a plug, when the depression deepens as the leaf dries, 

 cannot be determined wdth certainty, but it appears to be probable. 



Many of the epidermal cells contain one, or sometimes two bodies, which are more or 

 less club-shaped (this varying somewhat in shape and size) and resemble cystoliths. Each 

 is attached to the outer wall of the cell by a short stalk, which is in some cases very 



