158 BOTANICAL GAZETTE ~ [aveust 
investigation of SETCHELL** on the last two genera and Thalassiophyllum— 
' GWYNNE-VAUGHAN” has had the opportunity to study the anatomy of the 
Chinese marattiaceous genus Archangiopteris, established in 1899 by Crist 
and GIESENHAGEN.. Only a single small specimen was available, but if it repre- 
sents the structure of the larger stems, the genus has a simpler anatomical struc- 
ture than any of the other Marattiaceae. The single internal vascular strand 
characteristic of young plants of Angiopteris, Marattia, and Danaea, persists 
in the mature stem of Archangiopteris. ‘The sporangia were examined by Pro- 
fessor Bower and reported as corresponding very closely in structure to those of 
Angiopteris.—J. M. C. oe 
IN AN INVESTIGATION of the fluctuations in the number of ray-flowers of 
Chrysanthemum segetum, Lupwtc?3 has attempted to answer the question how 
large a number of heads must be counted to insure trustworthy. determination 
of the modes. By counting in lots of fifty heads and adding the results, he comes 
to the conclusion that in this species 500 heads may be considered the lower limit; 
that in most species 1000 counts are necessary; and in some 10,000 or even 20,000 
He deprecates the work done by American and English investigators who have 
contented themselves with biometric analysis of a couple hundred observations.— 
. SHULL. 
SETCHELL”* gives a brief account of several parasitic red algae found on the 
coast of California and describes a new genus, Peyssonneliopsis epi ‘phytica Setchell 
and Lawson, “growing in small dark red pustules scattered over the surface of 
membranaceous Rhodophyceae, sending rhizoidal filaments deep into the tissu 
of the host plant; antheridia and cystocarps unknown.” The form is said © 
differ from Cruoria “only in its parasitic habit and consequent. possession é 
thizoidal filaments penetrating the host plant.” It may perhaps be questioned 
a such characters alone justify the establishment of a new genus—B. M. 
— from the Acme variety of Lycopersicum esculentum produced only — 
© Potato-leaved tomato, which he calls I. solanopsis, and the latter then 
P pigieecc tl A., Post-embryonal stages of the Laminariaceae. Univ. Calif 
ub. Botany 2115-138. pls. 3. 1905. 
re WYNNE-VaucHaN, D. T., On the anatomy of Archangiopteris Henry - 
arattiaceae. Ann. Botany 19:259-271. pl. 10. 1905. 
2. . 
: 3 Lupwie, F., Zur Biometrie von Chrysanthemum segetum. Festschr. 20 
Son’s 70 stem Geburtstag, PP. 296-301. 1904. 
“SETCHELL, W. A., Parasitic Florideae of California. Nuova Notarisia. ™ 
59-63. Igo5. 
“95 Ware 
161. jigs. 2, 1905 
» C. A., The mutations of Lycopersicum. Pop. Sci. Monthly 67:15" 
ae 
