596 R. J. HARVEY-GIBSON AND MINNIE BRADLEY ON 



phloem and medullary rays. The tissue resembles in all respects that already 

 described for Glaucium. 



Hypecoum grandifiorum, Benth. — -The main stem is very short, most of the 

 aerial portion being formed of long slender leaves and floral axes bearing smaller 

 leaves arranged in a 2/5 spiral. The stem anatomy is as follows : The epidermis 

 is thin-walled and shows no definite cuticle, and beneath lie three layers of cells 

 containing either chlorophyll or red sap (fig. 21 ). The inner cells abut on an 

 amyliferous layer which is more evident in young plants. The sclerotic pericycle 

 follows next, and many of its cells are laticiferous. The vascular bundles are few in 

 number, only four occurring above the entry of the first leaf-trace. Each bundle is 

 surrounded by a sheath of collenchyma specially well developed on the inner side. 

 Laticiferous elements are present in all the tissues, and latex occurs even in the 

 xylem vessels (fig. 22). The tubes are unbranched. 



Dicentra formosa, DC. — The chief axis is obliquely ascending, its lower region 

 being covered with crowded leaf-bases, and its parenchyma is crammed with starch. 

 A transverse section of the floral axis exhibits a fluted outline with the larger 

 bundles occupying the angles. The epidermis is only slightly cutinised, and 

 the subepidermal tissue is poor in chlorophyll but rich in latex. The pericycle 

 varies in thickness and is sclerotic. Laticiferous tubes are present, but latex occurs 

 also in the ordinary cells of the pericycle. Latex tissue is also found in the cortex, 

 phloem, and wood parenchyma, and latex may even occur in the xylem vessels. 

 There is no branching or anastomosing of latex tubes (fig. 23). 



Adlumia cirrhosa, Raff. — The only available material was some stem fragments 

 showing leaf insertion, and hence the following account of the anatomy of this 

 species must necessarily be very incomplete. The plant is a climber, and has very 

 long slender ribbed stems (fig. 24). Immediately below the epidermis is a layer 

 of non-green cells representing an exodermis. The ridges of the stem are occupied 

 by bands of collenchyma, while the furrows are subtended by loose chlorophylliferous 

 tissue with large intercellular spaces opening on to stomata. A sclerotic pericycle 

 abuts on the collenchyma and chlorophyll-bearing tissue, but ends abruptly inwards. 

 The hard bast is deeply imbedded in the sclerotic pericycle, the whole forming a 

 continuous cylinder of mechanical tissue. The laticiferous tubes are solitary or in 

 short rows, and are found chiefly in the subepidermal layer, the cortex, soft bast, and 

 conjunctive parenchyma, but the latex tends to disappear as the stem gets older. 



Romneya trichocalyx, Eastw. — The exodermis in this form is fairly clearly 

 defined. The subjacent chlorophylliferous zone is discontinuous, and separated into 

 bands by non-green plates (fig. 25). The inner cortex from which these plates arise 

 consists of ordinary parenchyma ten to twelve layers deep. No endodermis or 

 pericycle is distinguishable. The elements of the xylem are worthy of note. Spiral 

 thickenings occur on their walls in conjunction with more or less bordered pits. 

 The material available was old, and here as in other species the latex tends to dis- 



