WATER STARWORT FAMILY 433 



with dots or stellate pits. Flowers monoecious, axillary and solitary, or 2 or 3 

 together in one axil, without calyx or corolla but often with two membranous bracts 

 which may become inflated. Staminate flower consisting of 1 terminal stamen. 

 Pistillate flower consisting of a 4-celled ovary with 2 filiform stigmas. Fruit 

 4-lobed, splitting at maturity into as many nutlets; nutlets (in ours) flattened; 

 seeds enclosed in a hyaline envelope. — Genus 1, species 2 to 25, as variously esti- 

 mated; all continents. 



Note on the inflorescence. — The flowers are always axillary. In California material (both 

 in the open and in cultures) only one pistillate flower has been found in an axil. Staminate 

 flowers have not been seen in submerged plants in cultures, yet these plants produce seed. The 

 distribution of flowers is as follows: (a) an axil may be bisexual, that is with one pistillate 

 flower and 1, 2 or 3 staminate flowers; (b) an axil may be unisexual with only one pistillate 

 flower; (c) an axil may be unisexual with 1, 2, or 3 staminate flowers (H. L. Mason). 



Bibliog. — Clarke, C. B., On the structure and affinities * * * of Callitrichaceae (Trans. Linn. 

 Soc. 22:411-412, — 1859). Hegelmaier, F., Monographic der Gattung Callitriche, 1-64, t. 1-4 

 (1864) ; Beitrag zur Kenntniss der Wassersterne (Verhand. Bot. Ver. Brandenb. 10:100-121, — 

 1868). Schenck, H., Vergleichende Anatomie der submersen Gewachse (Biblio. Bot. 1:1-67, 

 t. 1-10,-1886). Schrenk, J., Notes on the inflorescence of Callitriche (Bot. Gaz. 13:296-299,— 

 1888). Morong, Thos., [Notes on N. Am. Callitriches], (Bull. Torr. Club 18:232-239,-1891). 

 Fenley, Kittie L., The Calif ornian species of Callitriche (1932), ms. 



1. CALLITRICHE L. Water Starwort 



The only genus. (Greek kallos, beautiful, and trichos, a hair, on account of the 

 slender stems. ) 



Note on variation and habitat. — The question as to what extent the structures of species in 

 this genus are affected by the environment is one which must eventually be answered by cultural 

 studies. Through cultures made by Kittie L. Fenley at the University of California in 1931 and 

 1932, it was shown that Callitriclie marginata, C. palustris var. bolanderi, and C. autumnalis, 

 grown under the same conditions, retain their distinctive characteristics. C. autumnalis, known 

 only as an entirely submersed species, did not grow Avhen emcrsed, until a cover placed upon the 

 container brought the atmosphere nearly to a saturated condition. Callitriche marginata formed 

 the terminal rosette of floating-type leaves even when entirely submersed. Callitriche palustris 

 seemed to be adversely affected by some unknoA\Ti factor and produced smaller leaves than 

 naturally. Callitriche palustris var. bolanderi produced the characteristic long linear leaves, 

 and as the water receded floating-type leaves appeared at nodes once submersed. The fruits 

 throughout the genus tend to become hypogaeous when in contact with soil; this condition is, 

 therefore, of no value as a segregating character for the species. 



Fruit peduncled; plants terrestrial or amphibious; bracts present or absent 1. C. marginata. 



Fruit sessile or subsessile ; plants mainly aquatic (sometimes terrestrial or amphibious). 

 Leaves floating or submersed ; emersed leaves obovate or spatulate. 



Stems usually stout, leafy 2. C. palustris. 



Stems filiform, naked below; leaves mostly terminal 3. C. stenocarpa. 



Leaves linear, all submersed 4. C. autumnalis. 



1. C. marginata Torr. Wallow Starwort. Plants rooting from the nodes, 

 mainly terrestrial, forming dense prostrate mats, or sometimes partly submersed; 

 stems 2 to 6 inches long ; leaf -blades of terrestrial plants or blades of the emersed 

 floating leaves spatulate to oblanceolate, 3-nerved, 1 to 3I/2 lines long; blades of 

 submersed leaves linear-acuminate or linear to oblanceolate or spatulate, the apices 

 obtuse or rounded, 4 to 7 lines long; bracts usually none, if present minute, filiform 

 crescent-shaped (% to % line long) ; peduncles stout, spreading, 1 to 3 (or 5) lines 

 long, often deflexed and hypogaeous; fruits dark gray, slightly broader than long, 

 notched at base and apex, 1/3 to I/2 line long, the lobes conspicuously wing-margined, 

 the proximate diverging about % line ; styles persistent, % to 1 line long, becom- 

 ing brown and filiform (almost capillaiy), reflexed over the fruit, and slightly 

 exceeding it. 



Wet mud or shallow fresh water pools, 100 to 1250 feet : Coast Ranges from 

 Humboldt Co. to Monterey Co.; central Great Valley; San Bernardino Valley. 

 East to Arizona. Chile. Mar.-June. 



