166 MINNESOTA BOTANICAL STUDIKS. 



ta quae ant de ramis nltiniis deest aut in his raniis levis est et ra- 

 mulis corticalibus tegitur ; axile strato (in emollita) cartilagineo, in 

 partibns ramoniin inferioribus et in frondis axi fasciculis corticali- 

 bus decedentibus exposito, filis aliis latioribus aliis tenuioribus in- 

 tertextis composito, filis tenuioribus primum ])aucis. paulatim pluri- 

 bus et in partibus frondis veterioribus ])lurimis; strato corticale 

 ramorum ramulis verticaliter exeuntibus inferne cellulis angustis 

 cylindraceis instructis, supra axillis acutissimis subfrequenter di- 

 chotomis, superne in corymbos terminales filorum ultimorum bi- 

 tricellulatorum conglutinatorum exeuntibus cellulis breviter ovatis 

 composito; cystocarpiis involucro filorum ramulis ultimis strati cor- 

 ticalis consimilibus circumdatis ; antheridiis ad cellulos ultimos ra- 

 mulorum corticalium elongatos fasciculis parvis factis. 



Attached to rocks on sandy beach at low tide, on a rocky penin- 

 sula, two miles north of Waianae, Oahu. June 12, 1900. (J. E. T. 

 983, 1564.) The species dififers from L. dccussata in the granular 

 incrustation, the clavate form of the smaller branches, and in the 

 size and form of the cells of the cortical branchlets. It apparently 

 is closely allied to L. orientalis J. Ag. and may be the form mention 

 ed by Agardh (Anal. Algol. 3:100) as collected in Japan by the 

 Wright expedition and in Australia by J. B. Wilson. 



The abundantly dichotomous cortical branchlets cover only the 

 distal parts of the branches. Thev consist below of elongated 

 cylindrical cells about 8 mic. wide, and above of shorter and more 

 ovate cells, the terminal cells averaging 9-10x14-15 mic. In an- 

 theridia-bearing branches, however, the terminal cells are elongated 

 obovate, 4-6x10-20 mic. The transition from long cylindrical to 

 ovate cells is gradual. Branching seldom occurs at every cell even 

 in the terminal corymbose portion of the branchlet and the ultimate 

 filaments are usually unbranched for the last two or three cells. 

 These cortical branchlets are deciduous in the older parts of the 

 frond and are then replaced by short filaments often unbranched 

 and usually only 3-6 cells long. This occurs everywhere along the 

 main axis of the frond and in the basal parts of the branches. 

 Where this occurs the calcareous crust is exposed, when not itself 

 deciduous, while in the younger parts it is enclosed as a granular 

 mass among the cortical branchlets the corymbose tips of which 

 project above it, so that the lime is not evident in dried material. 



