117 



organisms and restricts the meaning of saprophyte to " those 

 species which derive their supply of food from organic products 

 directly, without the intervention of the activity of chlorophyl 

 and unaided by other organisms." In the last conception of the 

 term, Wullschlaegelia apliylla, a near relative of Ncottia, the so- 

 called bird's-nest orchid, described by Johow, * is the only seed- 

 plant known to be a true saprophyte, with the exception of 

 Hexalcctris apliyllns. 



Hexalectris apliyllus is a monotypic orchid of the southern 

 United States and Mexico, where it grows in relatively dry, 

 sandy soil, mixed with humus. It usually occurs singly, and 

 though the rhizomes are perennial, the appearance of the blos- 

 som one season by no means assures its being found in the same 

 locality the following year. The plant consists of a fleshy, 

 succulent, scaly rhizome (Figs. 4 and 5) from 7 cm. to 15 cm. 

 long and from 5 mm. to 1 5 mm. in diameter, which sends out 

 branches from its ring-like nodes and terminates in a scape from 

 20 cm. to 40 cm. in height. The scape bears purplish scales, 

 the lower truncate and sheathing, the upper acuminate, and 

 terminates in a raceme of from eight to twelve brownish-purple 

 flowers. The rhizome has no roots, though it is wrongly figured 

 in Britton and Brown's "Illustrated Flora" (Fig. 1146) as pos- 

 sessing coralloid roots. It has no trichomes, and no stomata 

 could be found in the epidermis of the rhizome though they are 

 present in small number in the epidermis of the scape and its 

 scale leaves. The epidermis of the rhizome consists of prism- 

 shaped cells flattened radially, their long axes extending in a 

 direction at right angles to that of the axis of the stem. The 

 outer walls have reticulate thickenings (Fig. 3), which correspond 

 in appearance to the epidermal cells of the roots of some epiphytic 

 orchids. They contain protoplasm and have large nuclei (Fig. 2, e). 

 Within the epidermis are one or two rows of short columnar cells 

 and within these the large thin-walled turgid cells which form the 

 bulk of the rhizome. The large nucleus in each cell lies in the 

 protoplasm near the wall and the remaining cell contents are fluid 

 with the exception of small bluish granules, probably proteid, in 



*Jahrb. wiss. Bot. 16: 445. 1885. 



