1 74 P>'of. Don's Descriptions of two new Genera of the 



rima, parva, adpresse 4-fariam iinbricata, ovata, obtusa, coriacea, Isevis- 

 siraa, nitida, viridia, 1 — 2 lineas longa, hinc obsolete carinata, inde con- 

 cava, basi lata adhserentia, margine perangusto scarioso. Amenta mas- 

 cula in ramulorum apice solitaria, sessilia, laxfe capitata, basi squamis 

 (foliis mutatis) pluribus, oblongis, obtusissimis, inde concavis, margine 

 scarioso-membranaceis involuerata. Squamae antheriferce pauciores et 

 majores, ellipticee, obtusse, inde concavse, rufescentes, margine membra- 

 nacese : ungue angustfe lineari, compresso. Antherarum thecce 2, ovatse, 

 obtusse, ad periphseriam inferam rima bivalvi dehiscentes. Amenta Jos- 

 minea subrotundo-ovata, omnin6 ut in pra;cedente, sed squamae pauciores 

 et paull6 latiores. Strobili dupl6 minores, subrotundi : squamis cuneato- 

 lanceolatis, lignosis, stipitatis, regione placentifera maximfe protuberanti, 

 quasi subpeltata, trigona, superficie inaequali : stipite compresso-tetra- 

 gono : apice triangulari-ovato, acuto, incumbenti. 



The habit of this singular genus recalls to mind the Lepidodendra, those 

 forms which at present exist only in a fossil state , the axis is studded with 

 the persistent adherent bases of the leaves, resembling the lozenge-shaped 

 marks on the stem of the fossil genus above-mentioned, and the ramification 

 frequently presents a dichotomous appearance, which arises from the nonde- 

 velopment of one of the lateral branches, the normal arrangement being a 

 primary axis with two opposite lateral branches. The bases of the leaves of 

 Lycopodiaceoe being so completely continuous with the axis would not pre- 

 sent such marks as those mentioned, and I am therefore inclined to consider 

 Lepidodendron as allied rather to Coniferce than to that family, and the in- 

 teresting genus above described appears to present us with an evident link of 

 connexion. I have not had an opportunity of examining the internal struc- 

 ture of Lepidodendron, but it is a subject well deserving investigation to 

 ascertain whether the vessels composing its woody tissue present that uni- 

 formity and dotting which prevail throughout Coniferve. 



The female spike in Athrotaxis, unlike that of most of the other genera of Cu- 

 pressinew, forms a regular strobilus as in Pinus, and the scales are very thick, 

 woody and persistent, as in the normal group of that genus. I have assumed 

 that they are composed of a bracte and pericarpium, which are here completely 



