322 BOTANICAL GAZETTE [october 



long, one or few-flowered peduncle, fleshy, white, oval floral leaves, and its 

 great predilection for wet or moist places, reveals its descent from the relatives 

 of the Nymphaeaceae, and it manifestly has nothing to do with the Saxi- 

 fragaceae, which are nearly related to the Rosaceae. Apart from the peculiar 

 staminodia, which are evidently morphologically equivalent to the staminodia 

 of many Nymphaeaceae, the fibers (Faden) in the Rafflesia, flower, and the 

 corona of Passiflora y Parnassia fits closely to Drosera through its leaf-rosette, 

 its long, almost leafless shaft, the calyx, the five beautiful white petals, the 

 sessile stigmas, the numerous parietal ovules, the method of capsule opening, 

 the small oblong seed, rich in endosperm, and moist habitat. Through its 

 four-leaved (four-carpellate) seed coat it approaches Nepenthes also. 



A summary of the parts studied by way of comparison may 

 be helpful. 



i. The ovule of Parnassia and Drosera are of the same shape, 

 and both have large air spaces developed. That of Saxifraga is 

 very compact and much thicker, and with thicker integuments. 



2. In Parnassia the archesporium of the ovules is hypodermal 

 and forms no new cells above it. Drosera usually develops in the 

 same way, but sometimes there is a single layer of cells between the 

 mother cell and the epidermis. All the Saxifragaceae studied form 

 the archesporium in the same way, but by the time the mother cell 

 stage is reached there are several layers of cells above it. 



3. In Parnassia the embryo sac comes to lie next to the integu- 

 ment except the very basal portion, all the nucellar cells above and 

 at the side having been destroyed. In Drosera the nucellar cells 

 above the sac have a squeezed appearance and are occasionally 

 destroyed completely. At the side and below the sac the layer 01 

 cells next the epidermis enlarge very greatly, giving the nucellus 01 

 Drosera a very peculiar appearance. This may be only another 

 means of decreasing the specific gravity of the seed. The sac of the 

 Saxifragaceae has several layers of nucellar cells above it. 



4. All three genera have an enormous development of the 

 filiform apparatus of the synergids, and the notch is also strikingly 

 developed. The filiform apparatus is pointed in Parnassia and 

 Saxifragaceae, and less pointed or more dome-shaped in Drosera. 



5. The primary endosperm nucleus in Parnassia and in 

 Drosera is immediately below the egg. In Saxifraga it is almost in 

 contact with the antipodals, and in Heuchera it is far below the egg- 



