42 WEST AUSTRALIAN PITCHER- PLANT, 



The stiff hairs alluded to before are thus described by Professor 

 Dickson (4) "Each is an elongated cell with pointed extremity, and 

 a broad truncated base imbedded in a slightly elevated group of 

 epidermis cells. This unicellular hair is solid from the tip to 

 within J or ^ of the distance from the base. The cell cavit}- 

 thus reduced is bounded by a distinct and highly refractive wall, 

 and the appearance is thus produced of one cell encapsulated in 

 another. According to the modern view of cell-thickening by 

 interstitial intussusception, this would be a remarkable case of 

 the differentiation of thickened cell-wall into two layers of 

 different character. The hairs are minutely tuberculated on the 

 outer surface." This is a very good description of these curious 

 emergences, and needs little to be added. On the young pitchers 

 the hairs are silvery- white (and almost as long as they are in older 

 ones, so that they look like little vegetable porcupines), but when 

 cleared with clove oil and examined under the microscope, there 

 is a faint yellow coloration in the interior of the hair; and in 

 older hairs it becomes a dark brown, sometimes quite opaque. 

 In both old and young hairs the contents are granular. Alto- 

 gether they bear a strong resemblance to those of some mammals. 

 Some of them show one or more constrictions along their length 

 (fig. 5 b). They are largest on the petioles and shortest on the 

 wings. They are, as Prof. Dickson mentions, tuberculous on the 

 external surface, but this can only be seen in dry and spirit- 

 mounted specimens, the tubercles disappearing in clove oil or 

 glycerin. The older hairs very often have the hyphse of a fungus 

 wound round them in spiral lines (fig. 5 c), and sometimes these 

 penetrate to the cavity, in which case they grow straight up 

 along the sides. I sent a slide to Mr. D. McAlpine, who was 

 good enough to send me the following note: — ^' Helminihosporuin 

 spp. Hyphse olivaceous, wavy, septate, not constricted at septa, 

 branching, 2|-3 /x broad, permeating cuticle and passing into hairs. 

 Spores smoky-brown, 3-septate, constricted at septa, rounded at 

 both ends, cylindric to fusiform, produced at the end of the 

 branches, 20-23 x 4|-6 /z, average 22 x 5 /i." It will be noticed in 

 the figure that some of the spores are 4-septate. 



