Prof. Nees von Esenbeck on New Holland Plants. 45 
which in their interior contain plate-like rings and spirals 
raised on the narrow edge, which constitute nearly the entire 
mass of the wood of the Mammillarie, Echinocacti, and Melo- 
_ cacti ; and also occur in small quantity in the Opuntie, espe- 
cially at the contractions of the joints, and which were first 
described by Meyen from Opuntia cylindrica. 
EXPLANATION OF PLATE. 
Fig. 1.—10. Stages of the formation of the annular vessels from Campelia 
Zanonia, Rich. Explanation in text, page 42. 
Fig. 11. Commencement of the formation into a ring of a spiral from 
Equisetum arvense. 
Fig. 12. Spiroidea on a section through the medulla perpendicular to the 
bark; a. the side towards the medulla, b. that toward the bark. 
Fig. 13. ’Spiroidea on a section parallel to the bark. 
Fig. 14. The same as in fig. 13, with an intermediate series of cells cor- 
responding to a right wound spiral. 
Fig. 12—14. From young stems of Cucurbita Pepo. 
V.—Characters of new Genera and Species of New Holland 
Cyperaceze, Restiaceze, and Juncacez. By Prof. C. G. 
NEEs von EsenBECK. 
[Communicated by Professor Lindley. | 
A. GuUNNIANE. 
HeELorTurRix. 
Locus inter Cyperaceas Acroiepideas. 
Gen. Cuar. Spicula disticha, squamis duabus inferioribus minori- 
bus sterilibus, duabus superioribus hermaphroditis. Stamina 
tria. Perigynii sete 4 (an semper?) retrorsum scabre. Stylus 
bifidus, a basi bulbosa deciduus. Caryopsis biconyvexa, styli 
basi conica mucronata perigynioque stipata. 
Inflorescentia : spicule axillares et terminales geminz brevipedun- 
culate. 
Plante pusille habitu Acrolepidis, Schrad. aut Eleogitonis, in inundatis 
degentes, diffuse. Culmus ramosus, flexuosus, foliosus. 
*974. Helothrix pusilla. Culmi 2—4 poll. longi, flaccidi, geniculati, 
_ compressi. Vaginz internodiis breviores, tote herbacee, striate 
ore truncate. Folia linearia, angusta, obtusa, margine scabra, 
trinervia. Spicule vix lin. 1. long ex vaginis superioribus 
emergentes, plereque geminz, pedunculis inclusis, oblonge, 
compress, virides cum purpura. Squame carinate, due in- 
feriores triplo majores uninerves acute, duz superiores ovato- 
lanceolate obtuse trinerves, apice virides, basi pallidz, decidue. 
Stylus bifidus, ramis longis tortis hirtis. Caryopsis candida, 
* The numbers refer to the collections of dried plants eres away by 
Mr. Gunn. 
