526 PROF. Е. О. BOWER ON APOSPORY AND ALLIED PHENOMENA. 
PLATE LIX. 
Polystichum angulare, var. pulcherrimum (continued). 
Fig. 24. Longitudinal section through the base of one of these protballoid growths when older; it shows 
how the vascular bundle (v.5.) may be traced a short way into the base of the prothalloid growth. 
( x 20.) 
Fig. 25. Transverse section of one of the cylindrical prothalloid growths above the ending of the vascular 
bundle. (x130.) 
Fig. 26. Heterocysts from tissue of the prothalloid growths. (x 175.) 
Fig. 27. One of the cylindrieal prothalloid growths which originate from the surface of the pinnule. 
ap=its apex, h=root-hairs, arch—archegonia, v.b.= vascular bundle of tbe pinnule. (х 10.) 
Fig. 28. Ditto: the apex is beginning to assume the distinctly flattened form. (x 10.) 
Fig. 29. Ditto, more advanced, with distinct flattened expansion at apex, as in normal prothallus. z= 
irregular lateral outgrowth. (х 10.) 
Fig. 30. Apex of pinnule, showing attempts to form prothalli both from the surface (prth. B) and from 
the apex (prth. 4). (х 20.) 
Fig. 81. An arrested sporangium, showing results of vegetative growth. (x 925.) 
Fig. 89. Ditto, more advanced, after culture at normal temperature for about three months ; two anther- 
idia (а) are already produced on it. sp=arrested sporangia which have not grown. (х 175.) 
Fig. 33. Section of sorus, after eight months’ culture, showing a prothalloid outgrowth, apparently from 
the stalk of а sporangium (sp), bearing an antheridium (anth). (x 70.) 
Figs. 34 & 35. Ditto, showing prothalloid outgrowths from base of sorus (b). (х 175.) 
Fig. 86. A sorus separated from the frond, and inverted, showing indusium (ind), arrested sporangia (s), 
and prothalloid outgrowths from the base of the sorus; one of these is elongated and fila- 
mentous: cultivated for three months. (х 70.) 
Athyrium Filix-femina, var. plumosum elegans. 
Fig. 37. Sorus in surface view, after a short period of germination on moist soil «=irregular out- 
growths ; s=sporangia. (х 20.) 
Fig. 38. Ditto, not germinated. (х 35.) 
Fig. 39. Ditto, germinated about two and half months. (х 20.) 
Fig. 40. Section through a sorus. (х 20.) 
Athyrium Filiz-femina, var. plumosum divaricatum. 
Fig. 41. Section through a sorus, showing sporangia (sp), an irregular outgrowth of the base of the 
sorus (2), and а bud (ap), with опе leaf (Г), also derived from the base of Ше sorus. (x 20.) 
Aspidium erythrosorum, Eat., var. monstrosum. 
Fig. 42. Section through the sorus, showing the indusium (ind) partly in surface view, the sporangia 
(sp), and the bud (bd), with a leaf (/) originating from the base of the sorus. (х 30.) 
Description оғ THE М оорсотз. 
Fig. 1, p. 319. A diagram illustrating the normal cycle of life of a Fern, and putting in relation with 
it the extensions of the cycle by sporophoric and oophorie budding, and also those short cuts 
which pass under the terms apospory and apogamy. 
Fig. 2, p. 324. A similar diagram of the cycle of life of Isoëtes ; the inner circle is intended to indicate 
how the cases described by Goebel may be graphically represented, supposing the view be 
. adopted that the sporophoric buds, which replace the sporangia, are really examples of excision 
. OË the sporal and sexual stages from the life-cycle. 
