-^ 100 - 
12. The cells of the venter undergo many divisions and develop 
a protective covering called the calyptra. 
13. By the middle of August a differentiation of cells is seen in 
the larger end of the young embryo. The inner ones are the arche- 
sporial cells and the outer ones will form the capsule wall. 
14. The calyptra which has kept pace with the growth of the em- 
bryo now ceases development. 
15. About August 15, the cells in the archesporial region differen- 
tiate into spore mother cells and elater-forming cells. 
16. The three regions of the sporogonium (capsule, seta, foot) 
begin to be evident. 
17. Development goes on with great rapidity until by the last of 
August the slightly lobed spore mother cells and nucleate elaters are 
to be seen occupying the space within the capsule. 
18. The sporogonium is now (Aug. 28) fully formed with its 
globular capsule, short seta, and pointed, conical foot. 
19. The wall of the capsule consists generally of two layers of 
cells, except in the region of the base where there are usually one or 
two more layers. 
20. Early in September the spore mother cells all become lobed. 
21. Throughout September and October the spore mother cells 
remain in the lobed condition and not until October do the spiral 
thickenings appear on the walls of the elaters. 
22. By the middle of November the lobed spore mother cells 
have divided to form the oval spores. 
23. By the last of November the first stages of germination have 
taken place, each spore being divided into a several-ceiled body. 
24. No further change takes place in the spores until they are 
shed in April. 
25. The abundance or lack of moisture has a marked influence on 
the development of the plants. Those growing in moist situations 
are more advanced on a given date than those of a drier location. 
26. Plants in a very moist habitat are very apt to be sterile. 
27. Those most thoroughly fruited are found on drier soil. 
ADDITIONS TO THE LICHEN FLORA OF SOUTHERN 
CALIFORNIA. No. 6. 
By H. E. HASSE, M. D. 
Heppia Zahlbruckneri spec. nov. 
Thallus of short, erect, terete to subterete lobules, 1 to 2 mm thick 
and 3 to 3.5 mm high, aggregated into groups and loosely attached 
to the substrate by medullary hyphae ; the apices are clavate to bul- 
bous, often spreading and assuming a flattened top ; the color is olive- 
green and darkening. The pseudoparenchymatous cortex, containing 
the gonidial layer, is 40 a thick, the pale green Scyionema gonidia are 
■ 1 
