Notes on Callitriche in Western North America

THE WASMANN JOURNAL OF BIOLOGY VoL. 27, No. 1 SPRING, 1969 Notes on Callitriche in Western North America PETER RUBTZOFF, DepMtment of Botany, Califomta Academy of Sciences, San Fmncisco, Califomia 94118. Although Fassett, who monographed the genus CaUitriche for the ~ew World (1951 ), worked with material from a large number of institutions in the eastern United States, the only in stitution in western North America from which he studied mater ial is the Herbarium of the University of California. This partly accounts for the less complete illumination by F assett of the situ ation in the \Vest, than has been done by him for eastern North America. Examination of Cctllitriche material at the herbaria of the Cahfornia Academy of Sciences (CAS), the University of California (UC), and the Dudley (DS) and J epson (JEPS) herbaria, and of C. longipedtmculata, C. ma1·ginata, and uniden tified Callit1 ·iche material from the herbarium of Pomona Uollege (PO:JI) and Rancho Santa Ana Botanic Garden (RSA) yielded additional information for western North America which I present in this paper. To the above institutions and to all persons who were of assistance in the present study, I express my deepest gratitude. Callitriche peploides Nuttall var. semialat a Fassett. This plant was collected in Ontario, San Bernardino County, California, as a "weed in lath house in low damp area & in gal. cans of camellias" at the Armstrong Nursery, Camblin, June 1, 1966 (CAS). Fassett (1951, pp. 163, 164) cited this variety from Mexico and Honduras only. Thomas C. Fuller (1967, p. 99) , on the basis of the same collection, recently reported it among weeds new to California. Callitriche anceps Fernald. Although this plant is cited by Fassett (1951, pp. 187, 188 ) [ 103 ] 104 THE WASMANN JOURNAL OF BIOLOGY, VoL. 27, 1969 from a large number of localities in eastern North America, only five collections from four widely scattered areas (Attn Island, Aleutians; Seward P eninsula, Alaska; Mt. Rainier, Washington; and Summit County, Utah) are listed by him for the '\Yest. I-Iulten (1960, p. 257) cites the plant from Alaska Peninsula, Alaska, Porsild (1951, p. 251) from Yukon, and Ta~d or (1966, p. 5) lists it for British Columbia. In this paper I shall call atten tion to additional occurrences of 0 . ctnceps in the \Iest. Before the citation of specimens, however, I shall discuss the status of the plant. Oallitt·iche anceps seems to be closely related to 0. heterophylla Pursh. Both occupy areas ranging across North America, but, although there is some overlap of the geographical ranges of the two, 0. anceps occupies essentially the northern half of the con tinent, extending south at high elevations, whereas 0 . hetet·o phylla occupies the southern half (see maps in Fassett, 1951, pp. 176, 178 [left], and 189) . On pages 188 to 190 of his treatment Fassett (1951) discusses several characters which were believed to differentiate 0 . anceps from 0 . heteTophylla, and decides that most of them are not good. The shape of the fruit, which is nar rower below the middle than above the middle in 0. hete·rophylla, and is essentially the same width below as above the middle in 0. anceps, he considers to be the most fundamental character separating the two. He also mentions the tips of veins in the linear submersed leaves, which, according to him, are slightly more excurrent in 0. anceps than in 0 . hetet·ophyllct . After having examined a number of plants of both species I decided that the variation present in this character, often even within one individual, diminishes its diagnostic value. The shape of the fruit seems to be a more consistent character, successfull~· appli cable in most instances, but not in all of them, since some varia tion in the shape of the fruit present in both 0. anceps and 0. heteTophylla makes this character overlap as well. Fassett (1951, p . 190) discusses this situation and mentions that some individ- FIGURE 1. Distribution of a. trochlea?"is (circles), a. longipeduncu lata (squares), and a. stagnalis (triangles, range shown for western North America only). Solid symbols: localities cited by Fassett (1951); open symbols: additional localities. ,, c..... -, I l_ 'i' r.. - r.. 0 N {J ,1} E-< , ~ l l- p -\. 0 p:: ·r )---j__ I:P I 0 ~ · ' ~ 0 ' p:: • ~ ""' J . c ~ · • · 0.... '-' p:: ..... E-< l<J r~ o ' ...... '----; ·o• - QJ- o0 • 'o ./' ~ 0 ~ ! 0 < 0 ~- )'? } ~ z <l 0 "' 'I r ~ .J '* rn 0 ""'E-< z0 106 THE WASMANN JOURNAL OF BIOLOGY, VoL. 27, 1969 uals in eastern North America show some degree of intermediacy between the two species. I found that the same, apparently, is true in the West, making it impossible to attribute some collec tions to either one species or the other on the basis of the known characters. It seems that experimental study is needed to deter mine the proper status of C. anceps, which possibly should be reduced to some subspecific category under C. hete1·ophylla. Some western North American collections may represent C. anceps, but could not be determined with certainty for the rea sons discussed above. Thus, Bolande1· 5090, from pools, Tuolumne River, 10,000 feet, 1866 (UC), although cited by Fassett (1951) under C. heteTophyllct var. BolandeTi (Hegelmaier) Fassett, seems to tend strongly toward C. anceps, or actually to represent that plant. The collection from Lamoille Lakes, Ruby Mountains, Elko C01.mty, Nevada, 9,500 feet, 111unz 16,238 in 19-±0 (CAS, POM, UC) may also be C. ance1Js. The following collections, however, I consider definitely to represent C. anceps. BRITISH COLUMBIA (since no localities are given in T. iVI. C. Taylor's list [1966] the following specimen known to me is cited here) : about 26 miles northeast of Anahim Lake, 52°43'N., 12-± 0 54'W., pond at treeline at about 6,200 feet, Calder, Pa1·m elee, & TayloT 20,217 in 1956 (DS, UC). CALIFORNIA: MoNo CoUN'l'Y : Fantail Lake, Lake Valley, northeastern base of \Vhite Mountain, southeastern boundary of Harvey i\'Ionroc Hall Natural Area, 10,000 feet, Clctusen 1758 in 1939 (CAS, DS, UC) . FRESNO CouN'I.'Y: near lowermost lake is Pioneer Basin, about 10,400 feet, Thomas 5477 in 1955 (CAS, DS); vicinity of lowest lake in Pioneer Basin, about 10,300 feet, Thom.as 6863 in 1957 (CAS). TuLARE CouN'l'Y: Eagle Lake, Sequoia K ational Forest, about 10,000 feet, F en·is & Lon·aine 11,24.4 in1946 (CAS, DS, UC). Callit1·iche anceps is pro b a b 1y more widespread in higher mountains of western North America than is reflected b~ · the above citations. However, Callit1·iche collections from high alti tudes commonly have immature fruits, and many collections which I suspect to represent C. cmceps could not be determined with certainty for that reason. NOTES ON CALLITRICHE-RUBTZOFF 107 Callitriche trochlearis Fassett. Fassett described C. t1·ochleaTis in 1951 (p. 194) when he mono graphed the genus, and, following the description, he cited five collections from four different localities, all of them in California: Buck Mountain and Eureka in I-Imnboldt Count:·, Ukiah in Mendocino County, and Cazadero in Sonoma Count:-. The collec tion from Eureka (1'mcy 824), however, represents very typical material of C. heterophylla var. BolancZM·i, and has been cited under C. trochlea-ris obviously erroneously. The present study revealed a number of coll ections of C. trochlea·ris which consid erably extend the range of the species as given by Fassett. Pre ceding the citations of these collections, however, a discussion on the variability in the fruit characters of the plant is giYen. <\.ctually, a greater degree of variation in certain fruit char acters is exhibited even by the small ammmt of material seen by Fassett, than is allowed for in his treatment. In the descrip tion of the species (p. 194) Fassett says "Fruit nearly round, 1.0-1.2 mm. in diameter," and in the key (p. 146 ) we read "fruit almost exactly as high as wide, always sessile." Actnall:r', the fruit was found to vary from round to somewhat elongate in shape, and was often found to be short-pedunculate, and should probably be called subsessile, rather than sessile. In the regional key (p. 220) the fruit width is given by Fassett again as 1.0- 1.2 mm., but the present writer found some fruits to measure as much as 1.5 1mn. in width. In the same key on p. 220 we read "Carpels broadly winged all around the margin." Actually the wing was often found to be quite narrow. Besides, the wing was not always found to be of equal width arotmd the carpel, as is stated in key on p. 146, but was often found to be somewhat broader at the summit of the mericarps. Callit1·iche tTochleaTis appears to be quite common in the Coast Ranges of California from Humboldt County to San :i\Iateo and Santa Clara counties, but has also been collected as far north as the V\Tillamette Valley in Oregon, as far south as northwestern San Luis Obispo County in California, and as far inland as the Sierra Nevada foothills in Calaveras County, California. A list of specimens lmo,vn to the writer, except for those already cited by Fassett ( 1951, p. 194), follows. 108 THE WASMANN JOURNAL OF BIOLOGY, VoL. 27, 1969 OREGON: LINN CouNTY: 1 mile northwest of Tangent, Stew a1"Cl 6345 in 1953 (CAS, DS). CALIFORNIA: IIm moLDT CouNTY: Alton, Tmcy 4025 in 1913 (UC); near summit of ridge between Van Duzen and Mad rivers on Dinsmore's Ranch, about 3,500 feet, TTCLcy 4277 in 1913 (UC).

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