254 BOTANICAL GAZETTE [SEPTEMBER 
remaining blue-green under the red to yellow rays. Porphyra remained red 
in the green-violet, but became green in the red-yellow. The pigments thus 
become of the complementary color to the incident light, and change in a time 
inversely proportional to the intensity of the light. The same change, but much 
slower, had been observed by the author in nature, and he considers this com- 
plementary chromatic adaptation the chief factor in determining the color of 
algae.—C. R. B. 
Pollen tubes of Cucurbitaceae.—Kirkwoop*° has been studying the behavior 
of the pollen tubes of Melothria pendula, Micrampelis lobata, and Cyclanthera 
explodens. He has noted that the time elapsing between pollination and the 
arrival of the tube at the embryo sac in these species is 26, 19, and 41 boas 
respectively. The tubes pass chiefly over the surface of the conducting pete 
lining the stylar canal and covering the “placental lobes,” and this is rich in 
starch. The suggestion is made that the tube is directed by “nutritive sub- 
stances secreted by the conducting tissue,” and that it “comes. under the influence 
of a stronger stimulant emanating from the ovule,” and “the source of this 
stimulus may be the endosperm nucleus.” —J. M. C 
Morphology of Phyllocladus.—Miss Roper Tsons* has obtained some glimpses 
of Podocarpus from cultivated species and five collections of P. alpinus secured 
in New Zealand by Dr. Cockayne during 1902, 1903, and 1904. It is disap” 
pointing to learn that no critical stages were fixed, and that we are still - z 
= st to ea 
Taxaceae.—J. M. 
Parichnos in recent plants.—Hri13? has reached the conclusion that P&P 
ichnos, a name given by BERTRAND to the strand of thin-walled parce 
tissue accompanying the leaf trace in a species of Lepidodendron, is a 
among living species of Lycopodium and Isoetes by certain mucilage cana 
The tissue to which the name was given is simply an early developmental se 
of the canal. In recent plants parichnos is restricted chiefly to the sporophy 
as, for example, in Isoetes Hysirix, where two canals run longitudin 
side of the sporangium, but do not extend into the cortex of the stem, aS 
case in fossil forms.—J. M. C 
3° Kirkwoop, JosepH Epwarp, The pollen tube in some of the Cucurbitacea® 
Bull. Torr. Bot. Club 33:327-342. pls. 16-17. 1906. 
3* ROBERTSON, AGNES, Some points in the morphology of P: hyllocladus 
Hook. Annals of Botany 20:259-265. pls. 17-18. 1906. poe ol 
alpinus 
3 Hit, F. G., On the presence of a parichnos in recent plants. 
Botany 20:267-273. pls. 19-20. 1906. 
